ts.createSourceFile trims leading newlines, causing stored line numbers to mismatch

[Artur-]

🔎 Search Terms

createSourceFile newlines trim

🕗 Version & Regression Information

• This is the behavior in every version I tried, and I reviewed the FAQ for entries about createSourceFile

⏯ Playground Link

No response

💻 Code

import React from 'react';

export default function HelloWorldView() {
  return <span>Hello</span>;
}

🙁 Actual behavior

Given this TSX file, React tooling will store a source reference on the <span> element as e.g.

$0.__reactFiber$wzqrbgzp6o._debugSource

and it will contain

{
columnNumber: 10,
fileName: ".../something.tsx",
lineNumber: 7
}

However, if you feed the TSX file into ts.createSourceFile and look for an element on line 7, you will not find anything because the file has been changed to

import React from 'react';

export default function HelloWorldView() {
  return <span>Hello</span>;
}

and it only has 5 lines

🙂 Expected behavior

ts.createSourceFile does no transformations whatsoever on the given input

Additional information about the issue

No response

[RyanCavanaugh]

TS obviously preserves the line information enough to e.g. give you correct line numbers on the commandline when showing errors. Can you clarify which API you're calling and how?

[Artur-]

Not sure this is a meaningful test, reproducing what is shown in a larger case is always difficult. I will dig more into this tomorrow and ensure the problem is not elsewhere. Anyway, given a.ts

const ts = require("typescript");
const { readFileSync } = require("fs");

const sourceText = readFileSync("a.ts", {encoding: 'utf-8'});
const sourceFile = ts.createSourceFile('test.tsx', sourceText, ts.ScriptTarget.Latest, true);
console.log(sourceFile.getText());

and package.json

{
  "name": "tstest",
  "version": "1.0.0",
  "description": "",
  "main": "index.js",
  "scripts": {
    "test": "echo \"Error: no test specified\" && exit 1"
  },
  "author": "",
  "license": "ISC",
  "devDependencies": {
    "typescript": "^5.4.5"
  }
}

then running

node_modules/.bin/tsc a.ts && node a

outputs

const ts = require("typescript");
const { readFileSync } = require("fs");

const sourceText = readFileSync("a.ts", {encoding: 'utf-8'});
const sourceFile = ts.createSourceFile('test.tsx', sourceText, ts.ScriptTarget.Latest, true);
console.log(sourceFile.getText());

which includes trailing newlines but not leading ones.

[RyanCavanaugh]

Use getFullText() for that operation

[Artur-]

Ok, so now that I am aware of getFullText() I am guessing that the main problem is the use of getStart() and getEnd() instead of getFullStart() and getFullWidth() in our code. Where should I have been able to find out about full vs non-full versions of the methods?

[typescript-bot]

This issue has been marked as "Question" and has seen no recent activity. It has been automatically closed for house-keeping purposes.