Add .js extension to all relative ESM imports since typescript won't do it. Modified version of https://github.com/microsoft/TypeScript/issues/16577#issuecomment-310426634 . WARNING: Doesn't work on multiline imports, please verify all files after script run.

readme.md

WARNING: Doesn't work on multiline imports, please verify all files after script run. Modified version of microsoft/TypeScript#16577 (comment) .

Add .js extension to all relative ESM imports since typescript won't do it.

• microsoft/TypeScript#16577
• microsoft/TypeScript#42151

Usage

1. Set REPO_PATH env variable to list of paths (comma separated) to read .ts files from.

REPO_PATH=/Users/saurabhshri/IdeaProjects/{project-name}/src/,/Users/saurabhshri/IdeaProjects/{project-name}/tests

2. Run the script.

npm install
node add-js-extension-esm-relative-imports.js

add-js-extension-esm-relative-imports.js

"use strict";
const FileHound = require('filehound');
const fs = require('fs');

const paths = process.env.REPO_PATH
    ? process.env.REPO_PATH.split(",").map(path => path.trim())
    : (function () {
        throw new Error("set REPO_PATH to comma separated input path lists");
    })();

console.warn("Does not handle multi-line imports, verify after script run. Use at your own risk");
console.log("Processing repository on paths : ", paths);

const files = FileHound.create()
    .paths(paths)
    .ext('ts')
    .find();

files.then((filePaths) => {
    filePaths.forEach((filepath) => {
        fs.readFile(filepath, 'utf8', (err, data) => {
            let newContent = data.split("\n")
                .map(line => {
                    if (!line.startsWith("import")) {
                        return line;
                    }

                    const tokens = line.split(" ");
                    let modulePath = tokens.pop();

                    if (modulePath.startsWith("\"/") || modulePath.startsWith("\"./") || modulePath.startsWith("\"../")) {
                        if (modulePath.endsWith(";")) {
                            modulePath = `${modulePath.slice(0, -2)}.js";`
                        } else {
                            modulePath = `${modulePath.slice(0, -1)}.js";`
                        }
                    }
                    return [...tokens, modulePath].join(" ");
                })
                .join("\n");

            console.log(`writing to ${filepath}`)
            fs.writeFile(`${filepath}`, newContent, function (err) {
                if (err) {
                    throw err;
                }
                console.log(`complete ${filepath}`);
            });
        });
    })
});

package.json

{
  "name": "add-js-extension-esm-relative-imports",
  "version": "1.0.0",
  "dependencies": {
    "filehound": "^1.17.6"
  }
}