Registry / web-framework / promise-loader

promise-loader

library1.0.0jsnpmunverified

A Webpack loader that provides a promise-based alternative to bundle-loader for code splitting. It wraps lazy-loaded chunks behind a function that returns a Promise<module>, allowing you to control when the chunk is fetched. The loader requires a promise library parameter (e.g., 'bluebird', 'Q', or 'global'). Supports named chunks and filename/name substitutions in bundle names. Stable version 1.0.0, by Dan Abramov. Useful for single-page apps needing promise-based lazy loading with Webpack.

web-framework

npm install promise-loader

github ↗package ↗

INSTALL

IMPORT

SIG · PROMISE-LOADER

promise-loader

web-frameworkjavascriptv1.0.0

Install

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Import

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Disk

—

Pass rate

0/ 6

Env Coverage0 / 6

glibc

18–22

musl

18–22

Install & Compatibility

Where this runs

tested against v? · npm install

Install × environment matrix

Each cell = how many times install + import succeeded across repeated harness runs. Partial = flaky.
glibc = Debian/Ubuntu slim · musl = Alpine Linux

musl

node 18–226 runs

build_error

glibc

node 18–226 runs

build_error

Code

Verified usage

Verified import paths — ran on the pinned version, not inferred.

promise-loader

✓ const load = require('promise?bluebird!./file.js');

✗ import load from 'promise!./file.js';

This is a Webpack loader, not a module. You 'require' it with a query parameter specifying the promise library. ESM import will not work directly; use require or configure in webpack.config.js.

promise-loader with chunk name

✓ const load = require('promise?bluebird,editor!./editor.js');

✗ const load = require('promise?bluebird!./editor.js'); // missing chunk name

Chunk name is optional but if omitted, the chunk will have a numeric id. Specify as a comma-separated second parameter after the promise library.

promise-loader as a loader in webpack config

✓ { test: /\.i18n\.json$/, loader: 'promise?global,[name].i18n' }

✗ { test: /\.json$/, loader: 'promise?bluebird' }

Use the 'loader' property in a rule. The query string includes the promise library and optional chunk name pattern with [filename] or [name] substitutions.

This shows how to configure promise-loader in Webpack to load files ending with .async.js lazily using Bluebird promises.

// webpack.config.js module.exports = { entry: './index.js', output: { filename: 'bundle.js', path: __dirname + '/dist' }, module: { loaders: [ { test: /\.async\.js$/, loader: 'promise?bluebird' } ] } }; // index.js var load = require('./some.async.js'); load().then(function(module) { console.log(module); }).catch(function(err) { console.error(err); });

Debug

Known issues

breakingYou must specify a promise library as a query parameter; there is no default.

fix

Add a parameter like 'bluebird', 'Q', or 'global' to the loader query: require('promise?bluebird!./file.js').

affects: >=0.1.0

gotchaOnly 'lazy' mode is supported; unlike bundle-loader you cannot get an immediate synchronous require.

fix

Always use the returned function and await its promise. If you need synchronous loading, use bundle-loader instead.

affects: >=0.1.0

deprecatedLoader query syntax with '?' and ',' may be deprecated in newer Webpack versions in favor of options or resourceQuery.

fix

For Webpack 5+, consider using a custom rule with the 'use' property and options object, or use a different loader like @webpack-contrib/promise-loader.

affects: >=0.1.0

breakingThe 'global' promise parameter uses window.Promise; if unavailable, it will fail.

fix

Ensure a global Promise is present, either via native Promise or a polyfill like core-js or es6-promise.

affects: >=0.1.0

Errors

Common errors & fixes

Module not found: Error: Cannot resolve module 'promise'

The 'promise' package is not installed as a node_modules package; the loader is not being invoked correctly.

fix

Install the promise-loader package: npm install promise-loader --save-dev. Then use require('promise?bluebird!./file.js') with the loader prefix.

TypeError: load is not a function

The query parameter to specify the promise library is missing, causing the loader to return the module directly instead of a loading function.

fix

Add a query string with a promise library, e.g., require('promise?bluebird!./file.js'). Then load() returns a Promise.

Cannot find module 'bluebird'

The specified promise library (e.g., 'bluebird') is not installed or not available in the project's dependencies.

fix

Install the promise library: npm install bluebird. Alternatively, use 'global' if you have a global Promise.

Upgrade

Version history

1.0.0latest on npm

Audit

Dependencies

No dependency data recorded yet.

Agent activity

4 hits · last 30 days

node

Resources

githubhttps://github.com/gaearon/promise-loader ↗

packagehttps://www.npmjs.com/package/promise-loader ↗