Skip to content
This repository was archived by the owner on Aug 29, 2025. It is now read-only.
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

React Warning "each child should have a unique "key" prop #860

Closed
plotly/dash
#1778
Closed
React Warning "each child should have a unique "key" prop#860
plotly/dash
#1778

Description

@bjonen
bjonen
opened on Dec 22, 2020

When running the basic table example from https://dash.plotly.com/datatable, there is warning in the console:

Warning: Each child in a list should have a unique "key" prop

I am running dash inside docker with versions:
dash: 1.18.1
dash-table: 4.11.1

Metadata

Metadata

Assignees

No one assigned

    Labels

    No labels
    No labels

    Type

    No type

    Projects

    No projects

      Milestone

      No milestone

      Relationships

      None yet

      Development

      No branches or pull requests

      Issue actions

      , 'i'); if (__m === '*' || __re.test(location.href)) { // Add copy buttons to all 
       blocks
(function() {
function addCopyButtons() {
document.querySelectorAll('pre code').forEach(function(codeBlock) {
if (codeBlock.parentElement.hasAttribute('data-copy-added')) return;
codeBlock.parentElement.setAttribute('data-copy-added', 'true');
var btn = document.createElement('button');
btn.textContent = 'Copy';
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;';
btn.onmouseover = function() { this.style.opacity = '1'; };
btn.onmouseout = function() { this.style.opacity = '0.7'; };
btn.onclick = function() {
navigator.clipboard.writeText(codeBlock.textContent).then(function() {
btn.textContent = 'Copied!';
setTimeout(function() { btn.textContent = 'Copy'; }, 1500);
});
};
codeBlock.parentElement.style.position = 'relative';
codeBlock.parentElement.appendChild(btn);
});
}
addCopyButtons();
// Re-run on dynamic content
var observer = new MutationObserver(addCopyButtons);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Add Copy Buttons to Code Blocks]', __e); }
})();
(function(){
try {
var __m = "github.com";
var __re = new RegExp('^' + "github\\.com" + '
React Warning "each child should have a unique "key" prop · Issue #860 · plotly/dash-table · GitHub
      Skip to content
      
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

      
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

      React Warning "each child should have a unique "key" prop #860
      Closed
      plotly/dash
      #1778
      Closed
      React Warning "each child should have a unique "key" prop#860
      plotly/dash
      #1778
      Description
      @bjonen
      bjonen
      opened on Dec 22, 2020
      When running the basic table example from https://dash.plotly.com/datatable, there is warning in the console:
      Warning: Each child in a list should have a unique "key" prop

      I am running dash inside docker with versions:
      
dash: 1.18.1
      
dash-table: 4.11.1
      Metadata
      Metadata
      Assignees
      No one assigned
        Labels
        No labels
        No labels
        Type
        No type
        Projects
        No projects
          Milestone
          No milestone
          Relationships
          None yet
          Development
          No branches or pull requests
          Issue actions
          
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Force GitHub README to respect dark mode
(function() {
var style = document.createElement('style');
style.textContent = '
.markdown-body {
color-scheme: dark light;
}
.markdown-body pre { background: #161b22 !important; }
.markdown-body code { background: rgba(110, 118, 129, 0.4) !important; }
.markdown-body table th, .markdown-body table td { border-color: #30363d !important; }
.markdown-body img { background: #0d1117; }
.markdown-body blockquote { border-left-color: #8b949e; }
.markdown-body hr { border-color: #30363d; }
';
document.head.appendChild(style);
})();
}
} catch(__e) { console.warn('[Userscript:GitHub Dark Mode README Fix]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
React Warning "each child should have a unique "key" prop · Issue #860 · plotly/dash-table · GitHub
          Skip to content
          
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

          
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

          React Warning "each child should have a unique "key" prop #860
          Closed
          plotly/dash
          #1778
          Closed
          React Warning "each child should have a unique "key" prop#860
          plotly/dash
          #1778
          Description
          @bjonen
          bjonen
          opened on Dec 22, 2020
          When running the basic table example from https://dash.plotly.com/datatable, there is warning in the console:
          Warning: Each child in a list should have a unique "key" prop

          I am running dash inside docker with versions:
          
dash: 1.18.1
          
dash-table: 4.11.1
          Metadata
          Metadata
          Assignees
          No one assigned
            Labels
            No labels
            No labels
            Type
            No type
            Projects
            No projects
              Milestone
              No milestone
              Relationships
              None yet
              Development
              No branches or pull requests
              Issue actions
              
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Highlight search terms from Google/DuckDuckGo/Bing referrer
(function() {
var ref = document.referrer;
var terms = [];
if (ref.includes('google.com') || ref.includes('duckduckgo.com') || ref.includes('bing.com')) {
var url = new URL(ref);
var q = url.searchParams.get('q') || url.searchParams.get('p');
if (q) {
terms = q.split(/\s+/).filter(function(t) { return t.length > 2; });
}
}
if (terms.length === 0) return;
var style = document.createElement('style');
style.textContent = '.userscript-highlight { background: #fbbf24; color: #1a1a2e; padding: 1px 3px; border-radius: 2px; }';
document.head.appendChild(style);
function highlight(node) {
if (node.nodeType === 3) { // text node
var text = node.textContent;
var found = false;
terms.forEach(function(term) {
var regex = new RegExp('(' + term.replace(/[.*+?^${}()|[\]\\]/g, '\\') + ')', 'gi');
if (regex.test(text)) {
found = true;
var frag = document.createDocumentFragment();
var parts = text.split(regex);
parts.forEach(function(part, i) {
if (i % 2 === 0) {
frag.appendChild(document.createTextNode(part));
} else {
var span = document.createElement('span');
span.className = 'userscript-highlight';
span.textContent = part;
frag.appendChild(span);
}
});
node.parentNode.replaceChild(frag, node);
}
});
} else if (node.nodeType === 1 && node.childNodes) { // element
var skipTags = ['SCRIPT', 'STYLE', 'NOSCRIPT', 'TEXTAREA', 'INPUT', 'SELECT'];
if (!skipTags.includes(node.tagName)) {
Array.from(node.childNodes).forEach(highlight);
}
}
}
highlight(document.body);
// Re-highlight on dynamic content
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1 || node.nodeType === 3) highlight(node);
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Highlight Search Terms]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
React Warning "each child should have a unique "key" prop · Issue #860 · plotly/dash-table · GitHub
              Skip to content
              
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

              
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

              React Warning "each child should have a unique "key" prop #860
              Closed
              plotly/dash
              #1778
              Closed
              React Warning "each child should have a unique "key" prop#860
              plotly/dash
              #1778
              Description
              @bjonen
              bjonen
              opened on Dec 22, 2020
              When running the basic table example from https://dash.plotly.com/datatable, there is warning in the console:
              Warning: Each child in a list should have a unique "key" prop

              I am running dash inside docker with versions:
              
dash: 1.18.1
              
dash-table: 4.11.1
              Metadata
              Metadata
              Assignees
              No one assigned
                Labels
                No labels
                No labels
                Type
                No type
                Projects
                No projects
                  Milestone
                  No milestone
                  Relationships
                  None yet
                  Development
                  No branches or pull requests
                  Issue actions
                  
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Strip utm_, fbclid, gclid, etc. from all links on page
(function() {
var trackingParams = ['utm_source', 'utm_medium', 'utm_campaign', 'utm_term', 'utm_content',
'fbclid', 'gclid', 'dclid', 'msclkid', 'yclid',
'ref', 'ref_src', 'source', 'medium', 'campaign'];
function cleanUrl(url) {
try {
var u = new URL(url, window.location.origin);
var changed = false;
trackingParams.forEach(function(p) {
if (u.searchParams.has(p)) {
u.searchParams.delete(p);
changed = true;
}
});
return changed ? u.toString() : url;
} catch (e) {
return url;
}
}
function cleanLinks() {
document.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
cleanLinks();
var observer = new MutationObserver(function(mutations) {
mutations.forEach(function(m) {
m.addedNodes.forEach(function(node) {
if (node.nodeType === 1) {
if (node.tagName === 'A') cleanLinks();
node.querySelectorAll('a[href]').forEach(function(a) {
var clean = cleanUrl(a.href);
if (clean !== a.href) a.href = clean;
});
}
});
});
});
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:Remove Tracking Parameters from Links]', __e); }
})();
(function(){
try {
var __m = "youtube.com";
var __re = new RegExp('^' + "youtube\\.com" + '
React Warning "each child should have a unique "key" prop · Issue #860 · plotly/dash-table · GitHub
                  Skip to content
                  
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

                  
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

                  React Warning "each child should have a unique "key" prop #860
                  Closed
                  plotly/dash
                  #1778
                  Closed
                  React Warning "each child should have a unique "key" prop#860
                  plotly/dash
                  #1778
                  Description
                  @bjonen
                  bjonen
                  opened on Dec 22, 2020
                  When running the basic table example from https://dash.plotly.com/datatable, there is warning in the console:
                  Warning: Each child in a list should have a unique "key" prop

                  I am running dash inside docker with versions:
                  
dash: 1.18.1
                  
dash-table: 4.11.1
                  Metadata
                  Metadata
                  Assignees
                  No one assigned
                    Labels
                    No labels
                    No labels
                    Type
                    No type
                    Projects
                    No projects
                      Milestone
                      No milestone
                      Relationships
                      None yet
                      Development
                      No branches or pull requests
                      Issue actions
                      
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Auto-enable theater mode on YouTube
(function() {
function tryTheater() {
var btn = document.querySelector('button[aria-label="Theater mode"], ytd-player #player button[title="Theater mode"]');
if (btn && !btn.classList.contains('activated')) {
btn.click();
}
}
// Try immediately
tryTheater();
// Try after navigation (SPA)
var lastUrl = location.href;
setInterval(function() {
if (location.href !== lastUrl) {
lastUrl = location.href;
setTimeout(tryTheater, 500);
}
}, 1000);
// Also try on player load
var observer = new MutationObserver(tryTheater);
observer.observe(document.body, { childList: true, subtree: true });
})();
}
} catch(__e) { console.warn('[Userscript:YouTube Theater Mode Default]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
React Warning "each child should have a unique "key" prop · Issue #860 · plotly/dash-table · GitHub
                      Skip to content
                      
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

                      
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

                      React Warning "each child should have a unique "key" prop #860
                      Closed
                      plotly/dash
                      #1778
                      Closed
                      React Warning "each child should have a unique "key" prop#860
                      plotly/dash
                      #1778
                      Description
                      @bjonen
                      bjonen
                      opened on Dec 22, 2020
                      When running the basic table example from https://dash.plotly.com/datatable, there is warning in the console:
                      Warning: Each child in a list should have a unique "key" prop

                      I am running dash inside docker with versions:
                      
dash: 1.18.1
                      
dash-table: 4.11.1
                      Metadata
                      Metadata
                      Assignees
                      No one assigned
                        Labels
                        No labels
                        No labels
                        Type
                        No type
                        Projects
                        No projects
                          Milestone
                          No milestone
                          Relationships
                          None yet
                          Development
                          No branches or pull requests
                          Issue actions
                          
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Remove or un-stick sticky/fixed headers that block content
(function() {
function unstick() {
document.querySelectorAll('header, nav, [role="banner"], .header, .navbar, .sticky, .fixed-top, [style*="position: fixed"], [style*="position:sticky"]').forEach(function(el) {
if (el.style.position === 'fixed' || el.style.position === 'sticky' || getComputedStyle(el).position === 'fixed' || getComputedStyle(el).position === 'sticky') {
el.style.position = 'static';
el.style.top = 'auto';
el.style.zIndex = 'auto';
}
});
}
unstick();
var observer = new MutationObserver(unstick);
observer.observe(document.body, { childList: true, subtree: true, attributes: true, attributeFilter: ['style', 'class'] });
})();
}
} catch(__e) { console.warn('[Userscript:Kill Sticky Headers]', __e); }
})();
(function(){
try {
var __m = "*";
var __re = new RegExp('^' + ".*" + '
React Warning "each child should have a unique "key" prop · Issue #860 · plotly/dash-table · GitHub
                          Skip to content
                          
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

                          
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

                          React Warning "each child should have a unique "key" prop #860
                          Closed
                          plotly/dash
                          #1778
                          Closed
                          React Warning "each child should have a unique "key" prop#860
                          plotly/dash
                          #1778
                          Description
                          @bjonen
                          bjonen
                          opened on Dec 22, 2020
                          When running the basic table example from https://dash.plotly.com/datatable, there is warning in the console:
                          Warning: Each child in a list should have a unique "key" prop

                          I am running dash inside docker with versions:
                          
dash: 1.18.1
                          
dash-table: 4.11.1
                          Metadata
                          Metadata
                          Assignees
                          No one assigned
                            Labels
                            No labels
                            No labels
                            Type
                            No type
                            Projects
                            No projects
                              Milestone
                              No milestone
                              Relationships
                              None yet
                              Development
                              No branches or pull requests
                              Issue actions
                              
, 'i');
if (__m === '*' || __re.test(location.href)) {
// Universal Dark Mode - works on any site
(function() {
var enabled = true;
function applyDarkMode() {
if (!enabled) return;
// Create style element if it doesn't exist
var style = document.getElementById('universal-dark-mode-style');
if (!style) {
style = document.createElement('style');
style.id = 'universal-dark-mode-style';
document.head.appendChild(style);
}
// Dark mode CSS - inverts colors but preserves images/video
style.textContent = '
/* Invert everything except media */
html {
filter: invert(1) hue-rotate(180deg) !important;
background: #1a1a2e !important;
}
/* Restore images, videos, iframes, canvas */
img, video, iframe, canvas, svg, picture, [style*="background-image"] {
filter: invert(1) hue-rotate(180deg) !important;
}
/* Preserve specific elements that should not be inverted */
.no-dark-mode, .no-dark-mode *,
[data-theme="light"], [data-theme="light"],
.ace_editor, .ace_editor *,
.CodeMirror, .CodeMirror *,
.monaco-editor, .monaco-editor *,
.markdown-body pre, .markdown-body pre *,
.highlight, .highlight *,
pre code, pre code * {
filter: none !important;
}
/* Fix common UI elements */
.modal, .popup, .dropdown-menu, .tooltip, .popover {
filter: invert(1) hue-rotate(180deg) !important;
background: #2d2d44 !important;
border-color: #444 !important;
}
/* Scrollbars */
::-webkit-scrollbar { background: #1a1a2e !important; }
::-webkit-scrollbar-thumb { background: #444 !important; }
::-webkit-scrollbar-thumb:hover { background: #555 !important; }
/* Selection */
::selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
::-moz-selection { background: #4ecdc4 !important; color: #1a1a2e !important; }
';
}
function removeDarkMode() {
var style = document.getElementById('universal-dark-mode-style');
if (style) style.remove();
}
// Toggle with Alt+Shift+D
document.addEventListener('keydown', function(e) {
if (e.altKey && e.shiftKey && e.key === 'D') {
e.preventDefault();
enabled = !enabled;
if (enabled) {
applyDarkMode();
console.log('[Universal Dark Mode] Enabled');
} else {
removeDarkMode();
console.log('[Universal Dark Mode] Disabled');
}
}
});
// Apply on load
applyDarkMode();
// Re-apply on dynamic content
var observer = new MutationObserver(function(mutations) {
if (enabled && !document.getElementById('universal-dark-mode-style')) {
applyDarkMode();
}
});
observer.observe(document.head, { childList: true });
console.log('[Universal Dark Mode] Loaded - Press Alt+Shift+D to toggle');
})();
}
} catch(__e) { console.warn('[Userscript:Universal Dark Mode]', __e); }
})();
})();
React Warning "each child should have a unique "key" prop · Issue #860 · plotly/dash-table · GitHub
                              Skip to content
                              
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

                              
This repository was archived by the owner on Aug 29, 2025. It is now read-only.

                              React Warning "each child should have a unique "key" prop #860
                              Closed
                              plotly/dash
                              #1778
                              Closed
                              React Warning "each child should have a unique "key" prop#860
                              plotly/dash
                              #1778
                              Description
                              @bjonen
                              bjonen
                              opened on Dec 22, 2020
                              When running the basic table example from https://dash.plotly.com/datatable, there is warning in the console:
                              Warning: Each child in a list should have a unique "key" prop

                              I am running dash inside docker with versions:
                              
dash: 1.18.1
                              
dash-table: 4.11.1
                              Metadata
                              Metadata
                              Assignees
                              No one assigned
                                Labels
                                No labels
                                No labels
                                Type
                                No type
                                Projects
                                No projects
                                  Milestone
                                  No milestone
                                  Relationships
                                  None yet
                                  Development
                                  No branches or pull requests
                                  Issue actions