NumericLiteral nodes with value 9007199254740993 claim to have .text = 9007199254740992

[JoshuaKGoldberg]

TypeScript Version: 3.7.0-dev.20190907

Search Terms: numeric literal max value 9007199254740992 9007199254740993

Code

const ts = require("typescript");
const sourceFile = ts.createSourceFile("temp.ts", "9007199254740993", 99);
const literal = sourceFile.statements[0].expression;

// '9007199254740992'
console.log("Actual .text:", literal.text);

// '9007199254740993'
console.log("Expected .text:", literal.getText(sourceFile));

Expected behavior:

.text should be the direct textual representation of the literal's value, right?

Actual behavior:

...some kind of rounding behavior related to being above Number.MAX_SAFE_INTEGER?

Playground Link: https://astexplorer.net/#/gist/8ee21b9bb7973f0d0118658496cec5ec/9dcea811268d39e678732414b53d608e37747a63 - since this is an AST parser issue

Related Issues: Discovered while writing a codefix for #29863. 😆

[JoshuaKGoldberg]

Did a little bit of digging. This happens in checkBigIntSuffix (in scanner.ts):

TypeScript/src/compiler/scanner.ts

Line 1478 in 73a2146

: +tokenValue;

Removing that + fixes the issue. Happy to send a PR if this is desirable!

[lowr]

I found this issue while fixing #46195. Looking at the explanation for the text property of LiteralLikeNode (link), it seems like it is actually working as intended. I'm not sure it’s always been like so since when this issue was opened, though.

I could argue that the property name text is confusing as one would expect it to be the node's textual representation in the source code.

[RyanCavanaugh]

Agreed this is operating as documented.