add Callback Throttling #1311

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Open
add Callback Throttling#1311
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@chriddyp
chriddyp
opened on Jun 25, 2020

Throttling!

If your UI enables rapid user interaction & updates, then how do you prevent the server or the clientside JS from getting overloaded?

This has come up here and there over the years and we've solved pieces of this puzzle in different ways:

  1. When typing into a dcc.Input, users can prevent every single keypress from updating the callback by using buttons with State or on blur (tabbing or entering) with n_blur & n_submit
  2. In serverside callbacks, if many requests are made at the same time for the same callback, then we'll prune out redundant requests while they're in the queue - Callback chain refactoring and performance improvements #1254

This still laves some use cases:

  1. What if you want to allow keypress updates, but just less frequently?
  2. What about clientside callbacks that don't get the same network request pruning in Callback chain refactoring and performance improvements #1254?
  3. What about components that don't have an equivalent of "blur" or "enter" and aren't well suited for buttons & State? Like hoverData in dcc.Graph

One idea is to solve this in the framework level with:

@app.callback(Output(...), [Input(...)], throttle=500)

This would be the second keyword argument into app.callback. The first was introduced in 1.12.0 with prevent_initial_call=True, see #1228

If any community member is interested in exploring this idea, then see:

  1. Prevent initial call #1228 for an example of how to wire callback keyword arguments from the backend up to the frontend
  2. https://github.com/plotly/dash/blob/dev/dash-renderer/src/observers/requestedCallbacks.ts for where callbacks are queued up for requests. Some throttling logic might go in here. See Callback chain refactoring and performance improvements #1254 for some context on the State Machine refactoring
  3. Contributing guide: https://github.com/plotly/dash/blob/dev/CONTRIBUTING.md
  4. After you've made a little progress, please submit a PR early to let us know that you are working on this

Alternatively, this work (and the rest of our work) can be funded by directly by organizations: https://plotly.com/products/consulting-and-oem or prioritized by Dash Enterprise customers.

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      , 'i'); if (__m === '*' || __re.test(location.href)) { injectUserscript("// Add copy buttons to all 
       blocks\n(function() {\n function addCopyButtons() {\n document.querySelectorAll('pre code').forEach(function(codeBlock) {\n if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;\n codeBlock.parentElement.setAttribute('data-copy-added', 'true');\n \n var btn = document.createElement('button');\n btn.textContent = 'Copy';\n btn.style.cssText = 'position:absolute;top:4px;right:4px;padding:2px 8px;font-size:11px;background:#4ecdc4;border:none;border-radius:4px;color:#1a1a2e;cursor:pointer;opacity:0.7;transition:opacity 0.2s;';\n btn.onmouseover = function() { this.style.opacity = '1'; };\n btn.onmouseout = function() { this.style.opacity = '0.7'; };\n btn.onclick = function() {\n navigator.clipboard.writeText(codeBlock.textContent).then(function() {\n btn.textContent = 'Copied!';\n setTimeout(function() { btn.textContent = 'Copy'; }, 1500);\n });\n };\n codeBlock.parentElement.style.position = 'relative';\n codeBlock.parentElement.appendChild(btn);\n });\n }\n \n addCopyButtons();\n \n // Re-run on dynamic content\n var observer = new MutationObserver(addCopyButtons);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Add Copy Buttons to Code Blocks");
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '

      Skip to content
      add Callback Throttling #1311
      Open
      Open
      add Callback Throttling#1311
      Labels
      P3backlogfeaturesomething new
      Description
      @chriddyp
      chriddyp
      opened on Jun 25, 2020
      Throttling!
      If your UI enables rapid user interaction & updates, then how do you prevent the server or the clientside JS from getting overloaded?
      This has come up here and there over the years and we've solved pieces of this puzzle in different ways:
      1. When typing into a dcc.Input, users can prevent every single keypress from updating the callback by using buttons with State or on blur (tabbing or entering) with n_blur & n_submit
      2. In serverside callbacks, if many requests are made at the same time for the same callback, then we'll prune out redundant requests while they're in the queue - Callback chain refactoring and performance improvements #1254
      This still laves some use cases:
      1. What if you want to allow keypress updates, but just less frequently?
      2. What about clientside callbacks that don't get the same network request pruning in Callback chain refactoring and performance improvements #1254?
      3. What about components that don't have an equivalent of "blur" or "enter" and aren't well suited for buttons & State? Like hoverData in dcc.Graph
      One idea is to solve this in the framework level with:
      @app.callback(Output(...), [Input(...)], throttle=500)
      This would be the second keyword argument into app.callback. The first was introduced in 1.12.0 with prevent_initial_call=True, see #1228
      If any community member is interested in exploring this idea, then see:
      1. Prevent initial call #1228 for an example of how to wire callback keyword arguments from the backend up to the frontend
      2. https://github.com/plotly/dash/blob/dev/dash-renderer/src/observers/requestedCallbacks.ts for where callbacks are queued up for requests. Some throttling logic might go in here. See Callback chain refactoring and performance improvements #1254 for some context on the State Machine refactoring
      3. Contributing guide: https://github.com/plotly/dash/blob/dev/CONTRIBUTING.md
      4. After you've made a little progress, please submit a PR early to let us know that you are working on this
      Alternatively, this work (and the rest of our work) can be funded by directly by organizations: https://plotly.com/products/consulting-and-oem or prioritized by Dash Enterprise customers.
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Force GitHub README to respect dark mode\n(function() {\n var style = document.createElement('style');\n style.textContent = '\n .markdown-body {\n color-scheme: dark light;\n }\n .markdown-body pre { background: #161b22 !important; }\n .markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }\n .markdown-body table th, .markdown-body table td { border-color: #30363d !important; }\n .markdown-body img { background: #0d1117; }\n .markdown-body blockquote { border-left-color: #8b949e; }\n .markdown-body hr { border-color: #30363d; }\n ';\n document.head.appendChild(style);\n})();", "GitHub Dark Mode README Fix");
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

          Skip to content
          add Callback Throttling #1311
          Open
          Open
          add Callback Throttling#1311
          Labels
          P3backlogfeaturesomething new
          Description
          @chriddyp
          chriddyp
          opened on Jun 25, 2020
          Throttling!
          If your UI enables rapid user interaction & updates, then how do you prevent the server or the clientside JS from getting overloaded?
          This has come up here and there over the years and we've solved pieces of this puzzle in different ways:
          1. When typing into a dcc.Input, users can prevent every single keypress from updating the callback by using buttons with State or on blur (tabbing or entering) with n_blur & n_submit
          2. In serverside callbacks, if many requests are made at the same time for the same callback, then we'll prune out redundant requests while they're in the queue - Callback chain refactoring and performance improvements #1254
          This still laves some use cases:
          1. What if you want to allow keypress updates, but just less frequently?
          2. What about clientside callbacks that don't get the same network request pruning in Callback chain refactoring and performance improvements #1254?
          3. What about components that don't have an equivalent of "blur" or "enter" and aren't well suited for buttons & State? Like hoverData in dcc.Graph
          One idea is to solve this in the framework level with:
          @app.callback(Output(...), [Input(...)], throttle=500)
          This would be the second keyword argument into app.callback. The first was introduced in 1.12.0 with prevent_initial_call=True, see #1228
          If any community member is interested in exploring this idea, then see:
          1. Prevent initial call #1228 for an example of how to wire callback keyword arguments from the backend up to the frontend
          2. https://github.com/plotly/dash/blob/dev/dash-renderer/src/observers/requestedCallbacks.ts for where callbacks are queued up for requests. Some throttling logic might go in here. See Callback chain refactoring and performance improvements #1254 for some context on the State Machine refactoring
          3. Contributing guide: https://github.com/plotly/dash/blob/dev/CONTRIBUTING.md
          4. After you've made a little progress, please submit a PR early to let us know that you are working on this
          Alternatively, this work (and the rest of our work) can be funded by directly by organizations: https://plotly.com/products/consulting-and-oem or prioritized by Dash Enterprise customers.
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Highlight search terms from Google/DuckDuckGo/Bing referrer\n(function() {\n var ref = document.referrer;\n var terms = [];\n \n if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {\n var url = new URL(ref);\n var q = url.searchParams.get('q') || url.searchParams.get('p');\n if (q) {\n terms = q.split(/\\s+/).filter(function(t) { return t.length > 2; });\n }\n }\n \n if (terms.length === 0) return;\n \n var style = document.createElement('style');\n style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';\n document.head.appendChild(style);\n \n function highlight(node) {\n if (node.nodeType === 3) { // text node\n var text = node.textContent;\n var found = false;\n terms.forEach(function(term) {\n var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\\]\\\\]/g, '\\\\') + ')', 'gi');\n if (regex.test(text)) {\n found = true;\n var frag = document.createDocumentFragment();\n var parts = text.split(regex);\n parts.forEach(function(part, i) {\n if (i % 2 === 0) {\n frag.appendChild(document.createTextNode(part));\n } else {\n var span = document.createElement('span');\n span.className = 'userscript-highlight';\n span.textContent = part;\n frag.appendChild(span);\n }\n });\n node.parentNode.replaceChild(frag, node);\n }\n });\n } else if (node.nodeType === 1 && node.childNodes) { // element\n var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];\n if (!skipTags.includes(node.tagName)) {\n Array.from(node.childNodes).forEach(highlight);\n }\n }\n }\n \n highlight(document.body);\n \n // Re-highlight on dynamic content\n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1 || node.nodeType === 3) highlight(node);\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Highlight Search Terms");
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

              Skip to content
              add Callback Throttling #1311
              Open
              Open
              add Callback Throttling#1311
              Labels
              P3backlogfeaturesomething new
              Description
              @chriddyp
              chriddyp
              opened on Jun 25, 2020
              Throttling!
              If your UI enables rapid user interaction & updates, then how do you prevent the server or the clientside JS from getting overloaded?
              This has come up here and there over the years and we've solved pieces of this puzzle in different ways:
              1. When typing into a dcc.Input, users can prevent every single keypress from updating the callback by using buttons with State or on blur (tabbing or entering) with n_blur & n_submit
              2. In serverside callbacks, if many requests are made at the same time for the same callback, then we'll prune out redundant requests while they're in the queue - Callback chain refactoring and performance improvements #1254
              This still laves some use cases:
              1. What if you want to allow keypress updates, but just less frequently?
              2. What about clientside callbacks that don't get the same network request pruning in Callback chain refactoring and performance improvements #1254?
              3. What about components that don't have an equivalent of "blur" or "enter" and aren't well suited for buttons & State? Like hoverData in dcc.Graph
              One idea is to solve this in the framework level with:
              @app.callback(Output(...), [Input(...)], throttle=500)
              This would be the second keyword argument into app.callback. The first was introduced in 1.12.0 with prevent_initial_call=True, see #1228
              If any community member is interested in exploring this idea, then see:
              1. Prevent initial call #1228 for an example of how to wire callback keyword arguments from the backend up to the frontend
              2. https://github.com/plotly/dash/blob/dev/dash-renderer/src/observers/requestedCallbacks.ts for where callbacks are queued up for requests. Some throttling logic might go in here. See Callback chain refactoring and performance improvements #1254 for some context on the State Machine refactoring
              3. Contributing guide: https://github.com/plotly/dash/blob/dev/CONTRIBUTING.md
              4. After you've made a little progress, please submit a PR early to let us know that you are working on this
              Alternatively, this work (and the rest of our work) can be funded by directly by organizations: https://plotly.com/products/consulting-and-oem or prioritized by Dash Enterprise customers.
              Metadata
              Metadata
              Assignees
              No one assigned
                Labels
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Strip utm_, fbclid, gclid, etc. from all links on page\n(function() {\n var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',\n 'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',\n 'ref', 'ref_src', 'source', 'medium', 'campaign'];\n \n function cleanUrl(url) {\n try {\n var u = new URL(url, window.location.origin);\n var changed = false;\n trackingParams.forEach(function(p) {\n if (u.searchParams.has(p)) {\n u.searchParams.delete(p);\n changed = true;\n }\n });\n return changed ? u.toString() : url;\n } catch (e) {\n return url;\n }\n }\n \n function cleanLinks() {\n document.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n \n cleanLinks();\n \n var observer = new MutationObserver(function(mutations) {\n mutations.forEach(function(m) {\n m.addedNodes.forEach(function(node) {\n if (node.nodeType === 1) {\n if (node.tagName === 'A') cleanLinks();\n node.querySelectorAll('a[href]').forEach(function(a) {\n var clean = cleanUrl(a.href);\n if (clean !== a.href) a.href = clean;\n });\n }\n });\n });\n });\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "Remove Tracking Parameters from Links");
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '

                  Skip to content
                  add Callback Throttling #1311
                  Open
                  Open
                  add Callback Throttling#1311
                  Labels
                  P3backlogfeaturesomething new
                  Description
                  @chriddyp
                  chriddyp
                  opened on Jun 25, 2020
                  Throttling!
                  If your UI enables rapid user interaction & updates, then how do you prevent the server or the clientside JS from getting overloaded?
                  This has come up here and there over the years and we've solved pieces of this puzzle in different ways:
                  1. When typing into a dcc.Input, users can prevent every single keypress from updating the callback by using buttons with State or on blur (tabbing or entering) with n_blur & n_submit
                  2. In serverside callbacks, if many requests are made at the same time for the same callback, then we'll prune out redundant requests while they're in the queue - Callback chain refactoring and performance improvements #1254
                  This still laves some use cases:
                  1. What if you want to allow keypress updates, but just less frequently?
                  2. What about clientside callbacks that don't get the same network request pruning in Callback chain refactoring and performance improvements #1254?
                  3. What about components that don't have an equivalent of "blur" or "enter" and aren't well suited for buttons & State? Like hoverData in dcc.Graph
                  One idea is to solve this in the framework level with:
                  @app.callback(Output(...), [Input(...)], throttle=500)
                  This would be the second keyword argument into app.callback. The first was introduced in 1.12.0 with prevent_initial_call=True, see #1228
                  If any community member is interested in exploring this idea, then see:
                  1. Prevent initial call #1228 for an example of how to wire callback keyword arguments from the backend up to the frontend
                  2. https://github.com/plotly/dash/blob/dev/dash-renderer/src/observers/requestedCallbacks.ts for where callbacks are queued up for requests. Some throttling logic might go in here. See Callback chain refactoring and performance improvements #1254 for some context on the State Machine refactoring
                  3. Contributing guide: https://github.com/plotly/dash/blob/dev/CONTRIBUTING.md
                  4. After you've made a little progress, please submit a PR early to let us know that you are working on this
                  Alternatively, this work (and the rest of our work) can be funded by directly by organizations: https://plotly.com/products/consulting-and-oem or prioritized by Dash Enterprise customers.
                  Metadata
                  Metadata
                  Assignees
                  No one assigned
                    Labels
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Auto-enable theater mode on YouTube\n(function() {\n function tryTheater() {\n var btn = document.querySelector('button[aria-label=\"Theater mode\"], ytd-player #player button[title=\"Theater mode\"]');\n if (btn && !btn.classList.contains('activated')) {\n btn.click();\n }\n }\n \n // Try immediately\n tryTheater();\n \n // Try after navigation (SPA)\n var lastUrl = location.href;\n setInterval(function() {\n if (location.href !== lastUrl) {\n lastUrl = location.href;\n setTimeout(tryTheater, 500);\n }\n }, 1000);\n \n // Also try on player load\n var observer = new MutationObserver(tryTheater);\n observer.observe(document.body, { childList: true, subtree: true });\n})();", "YouTube Theater Mode Default");
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                      Skip to content
                      add Callback Throttling #1311
                      Open
                      Open
                      add Callback Throttling#1311
                      Labels
                      P3backlogfeaturesomething new
                      Description
                      @chriddyp
                      chriddyp
                      opened on Jun 25, 2020
                      Throttling!
                      If your UI enables rapid user interaction & updates, then how do you prevent the server or the clientside JS from getting overloaded?
                      This has come up here and there over the years and we've solved pieces of this puzzle in different ways:
                      1. When typing into a dcc.Input, users can prevent every single keypress from updating the callback by using buttons with State or on blur (tabbing or entering) with n_blur & n_submit
                      2. In serverside callbacks, if many requests are made at the same time for the same callback, then we'll prune out redundant requests while they're in the queue - Callback chain refactoring and performance improvements #1254
                      This still laves some use cases:
                      1. What if you want to allow keypress updates, but just less frequently?
                      2. What about clientside callbacks that don't get the same network request pruning in Callback chain refactoring and performance improvements #1254?
                      3. What about components that don't have an equivalent of "blur" or "enter" and aren't well suited for buttons & State? Like hoverData in dcc.Graph
                      One idea is to solve this in the framework level with:
                      @app.callback(Output(...), [Input(...)], throttle=500)
                      This would be the second keyword argument into app.callback. The first was introduced in 1.12.0 with prevent_initial_call=True, see #1228
                      If any community member is interested in exploring this idea, then see:
                      1. Prevent initial call #1228 for an example of how to wire callback keyword arguments from the backend up to the frontend
                      2. https://github.com/plotly/dash/blob/dev/dash-renderer/src/observers/requestedCallbacks.ts for where callbacks are queued up for requests. Some throttling logic might go in here. See Callback chain refactoring and performance improvements #1254 for some context on the State Machine refactoring
                      3. Contributing guide: https://github.com/plotly/dash/blob/dev/CONTRIBUTING.md
                      4. After you've made a little progress, please submit a PR early to let us know that you are working on this
                      Alternatively, this work (and the rest of our work) can be funded by directly by organizations: https://plotly.com/products/consulting-and-oem or prioritized by Dash Enterprise customers.
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Remove or un-stick sticky/fixed headers that block content\n(function() {\n function unstick() {\n document.querySelectorAll('header, nav, [role=\"banner\"], .header, .navbar, .sticky, .fixed-top, [style*=\"position: fixed\"], [style*=\"position:sticky\"]').forEach(function(el) {\n if (el.style.position === 'fixed' || el.style.position === 'sticky' || \n getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {\n el.style.position = 'static';\n el.style.top = 'auto';\n el.style.zIndex = 'auto';\n }\n });\n }\n \n unstick();\n \n var observer = new MutationObserver(unstick);\n observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });\n})();", "Kill Sticky Headers");
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '

                          Skip to content
                          add Callback Throttling #1311
                          Open
                          Open
                          add Callback Throttling#1311
                          Labels
                          P3backlogfeaturesomething new
                          Description
                          @chriddyp
                          chriddyp
                          opened on Jun 25, 2020
                          Throttling!
                          If your UI enables rapid user interaction & updates, then how do you prevent the server or the clientside JS from getting overloaded?
                          This has come up here and there over the years and we've solved pieces of this puzzle in different ways:
                          1. When typing into a dcc.Input, users can prevent every single keypress from updating the callback by using buttons with State or on blur (tabbing or entering) with n_blur & n_submit
                          2. In serverside callbacks, if many requests are made at the same time for the same callback, then we'll prune out redundant requests while they're in the queue - Callback chain refactoring and performance improvements #1254
                          This still laves some use cases:
                          1. What if you want to allow keypress updates, but just less frequently?
                          2. What about clientside callbacks that don't get the same network request pruning in Callback chain refactoring and performance improvements #1254?
                          3. What about components that don't have an equivalent of "blur" or "enter" and aren't well suited for buttons & State? Like hoverData in dcc.Graph
                          One idea is to solve this in the framework level with:
                          @app.callback(Output(...), [Input(...)], throttle=500)
                          This would be the second keyword argument into app.callback. The first was introduced in 1.12.0 with prevent_initial_call=True, see #1228
                          If any community member is interested in exploring this idea, then see:
                          1. Prevent initial call #1228 for an example of how to wire callback keyword arguments from the backend up to the frontend
                          2. https://github.com/plotly/dash/blob/dev/dash-renderer/src/observers/requestedCallbacks.ts for where callbacks are queued up for requests. Some throttling logic might go in here. See Callback chain refactoring and performance improvements #1254 for some context on the State Machine refactoring
                          3. Contributing guide: https://github.com/plotly/dash/blob/dev/CONTRIBUTING.md
                          4. After you've made a little progress, please submit a PR early to let us know that you are working on this
                          Alternatively, this work (and the rest of our work) can be funded by directly by organizations: https://plotly.com/products/consulting-and-oem or prioritized by Dash Enterprise customers.
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                          No one assigned
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, 'i');
if (__m === '*' || __re.test(location.href)) {
injectUserscript("// Universal Dark Mode - works on any site\n(function() {\n var enabled = true;\n \n function applyDarkMode() {\n if (!enabled) return;\n \n // Create style element if it doesn't exist\n var style = document.getElementById('universal-dark-mode-style');\n if (!style) {\n style = document.createElement('style');\n style.id = 'universal-dark-mode-style';\n document.head.appendChild(style);\n }\n \n // Dark mode CSS - inverts colors but preserves images/video\n style.textContent = '\n /* Invert everything except media */\n html {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #1a1a2e !important;\n }\n \n /* Restore images, videos, iframes, canvas */\n img, video, iframe, canvas, svg, picture, [style*=\"background-image\"] {\n filter: invert(1) hue-rotate(180deg) !important;\n }\n \n /* Preserve specific elements that should not be inverted */\n .no-dark-mode, .no-dark-mode *,\n [data-theme=\"light\"], [data-theme=\"light\"],\n .ace_editor, .ace_editor *,\n .CodeMirror, .CodeMirror *,\n .monaco-editor, .monaco-editor *,\n .markdown-body pre, .markdown-body pre *,\n .highlight, .highlight *,\n pre code, pre code * {\n filter: none !important;\n }\n \n /* Fix common UI elements */\n .modal, .popup, .dropdown-menu, .tooltip, .popover {\n filter: invert(1) hue-rotate(180deg) !important;\n background: #2d2d44 !important;\n border-color: #444 !important;\n }\n \n /* Scrollbars */\n ::-webkit-scrollbar { background: #1a1a2e !important; }\n ::-webkit-scrollbar-thumb { background: #444 !important; }\n ::-webkit-scrollbar-thumb:hover { background: #555 !important; }\n \n /* Selection */\n ::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }\n ';\n }\n \n function removeDarkMode() {\n var style = document.getElementById('universal-dark-mode-style');\n if (style) style.remove();\n }\n \n // Toggle with Alt+Shift+D\n document.addEventListener('keydown', function(e) {\n if (e.altKey && e.shiftKey && e.key === 'D') {\n e.preventDefault();\n enabled = !enabled;\n if (enabled) {\n applyDarkMode();\n console.log('[Universal Dark Mode] Enabled');\n } else {\n removeDarkMode();\n console.log('[Universal Dark Mode] Disabled');\n }\n }\n });\n \n // Apply on load\n applyDarkMode();\n \n // Re-apply on dynamic content\n var observer = new MutationObserver(function(mutations) {\n if (enabled && !document.getElementById('universal-dark-mode-style')) {\n applyDarkMode();\n }\n });\n observer.observe(document.head, { childList: true });\n \n console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');\n})();", "Universal Dark Mode");
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();

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                              add Callback Throttling #1311
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                              add Callback Throttling#1311
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                              P3backlogfeaturesomething new
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                              @chriddyp
                              chriddyp
                              opened on Jun 25, 2020
                              Throttling!
                              If your UI enables rapid user interaction & updates, then how do you prevent the server or the clientside JS from getting overloaded?
                              This has come up here and there over the years and we've solved pieces of this puzzle in different ways:
                              1. When typing into a dcc.Input, users can prevent every single keypress from updating the callback by using buttons with State or on blur (tabbing or entering) with n_blur & n_submit
                              2. In serverside callbacks, if many requests are made at the same time for the same callback, then we'll prune out redundant requests while they're in the queue - Callback chain refactoring and performance improvements #1254
                              This still laves some use cases:
                              1. What if you want to allow keypress updates, but just less frequently?
                              2. What about clientside callbacks that don't get the same network request pruning in Callback chain refactoring and performance improvements #1254?
                              3. What about components that don't have an equivalent of "blur" or "enter" and aren't well suited for buttons & State? Like hoverData in dcc.Graph
                              One idea is to solve this in the framework level with:
                              @app.callback(Output(...), [Input(...)], throttle=500)
                              This would be the second keyword argument into app.callback. The first was introduced in 1.12.0 with prevent_initial_call=True, see #1228
                              If any community member is interested in exploring this idea, then see:
                              1. Prevent initial call #1228 for an example of how to wire callback keyword arguments from the backend up to the frontend
                              2. https://github.com/plotly/dash/blob/dev/dash-renderer/src/observers/requestedCallbacks.ts for where callbacks are queued up for requests. Some throttling logic might go in here. See Callback chain refactoring and performance improvements #1254 for some context on the State Machine refactoring
                              3. Contributing guide: https://github.com/plotly/dash/blob/dev/CONTRIBUTING.md
                              4. After you've made a little progress, please submit a PR early to let us know that you are working on this
                              Alternatively, this work (and the rest of our work) can be funded by directly by organizations: https://plotly.com/products/consulting-and-oem or prioritized by Dash Enterprise customers.
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