tslib

This is a runtime library for TypeScript that contains all of the TypeScript helper functions.

This library is primarily used by the --importHelpers flag in TypeScript. When using --importHelpers, a module that uses helper functions like __extends and __assign in the following emitted file:

1var __assign = (this && this.__assign) || Object.assign || function(t) {
2    for (var s, i = 1, n = arguments.length; i < n; i++) {
3        s = arguments[i];
4        for (var p in s) if (Object.prototype.hasOwnProperty.call(s, p))
5            t[p] = s[p];
6    }
7    return t;
8};
9exports.x = {};
10exports.y = __assign({}, exports.x);
11

will instead be emitted as something like the following:

1var tslib_1 = require("tslib");
2exports.x = {};
3exports.y = tslib_1.__assign({}, exports.x);

Because this can avoid duplicate declarations of things like __extends, __assign, etc., this means delivering users smaller files on average, as well as less runtime overhead. For optimized bundles with TypeScript, you should absolutely consider using tslib and --importHelpers.

Installing

For the latest stable version, run:

npm

1# TypeScript 3.9.2 or later
2npm install tslib
3
4# TypeScript 3.8.4 or earlier
5npm install tslib@^1
6
7# TypeScript 2.3.2 or earlier
8npm install tslib@1.6.1

yarn

1# TypeScript 3.9.2 or later
2yarn add tslib
3
4# TypeScript 3.8.4 or earlier
5yarn add tslib@^1
6
7# TypeScript 2.3.2 or earlier
8yarn add tslib@1.6.1

bower

1# TypeScript 3.9.2 or later
2bower install tslib
3
4# TypeScript 3.8.4 or earlier
5bower install tslib@^1
6
7# TypeScript 2.3.2 or earlier
8bower install tslib@1.6.1

JSPM

1# TypeScript 3.9.2 or later
2jspm install tslib
3
4# TypeScript 3.8.4 or earlier
5jspm install tslib@^1
6
7# TypeScript 2.3.2 or earlier
8jspm install tslib@1.6.1

Usage

Set the importHelpers compiler option on the command line:

tsc --importHelpers file.ts

or in your tsconfig.json:

1{
2    "compilerOptions": {
3        "importHelpers": true
4    }
5}

For bower and JSPM users

You will need to add a paths mapping for tslib, e.g. For Bower users:

1{
2    "compilerOptions": {
3        "module": "amd",
4        "importHelpers": true,
5        "baseUrl": "./",
6        "paths": {
7            "tslib" : ["bower_components/tslib/tslib.d.ts"]
8        }
9    }
10}

For JSPM users:

1{
2    "compilerOptions": {
3        "module": "system",
4        "importHelpers": true,
5        "baseUrl": "./",
6        "paths": {
7            "tslib" : ["jspm_packages/npm/tslib@2.x.y/tslib.d.ts"]
8        }
9    }
10}

Deployment

• Choose your new version number
• Set it in package.json and bower.json
• Create a tag: git tag [version]
• Push the tag: git push --tags
• Create a release in GitHub
• Run the publish to npm workflow

Done.

Contribute

There are many ways to contribute to TypeScript.

• Submit bugs and help us verify fixes as they are checked in.
• Review the source code changes.
• Engage with other TypeScript users and developers on StackOverflow.
• Join the #typescript discussion on Twitter.
• Contribute bug fixes.

Documentation

• Quick tutorial
• Programming handbook
• Homepage