yaml-loader

library0.9.0jsnpmunverified

A Webpack loader that converts YAML files into JavaScript objects or JSON strings, using the `yaml` library for parsing. The current stable version is 0.9.0, released with support for Webpack 5+ and Node.js 20+. It offers options like `asJSON` for JSON output, `asStream` for parsing multi-document YAML streams, and `namespace` for extracting specific sub-trees. Unlike alternatives like js-yaml-loader, this loader leverages the more modern `yaml` package and is actively maintained. Release cadence is irregular, with major version bumps for breaking changes.

serialization

npm install yaml-loader

github ↗package ↗

INSTALL

IMPORT

SIG · YAML-LOADER

yaml-loader

serializationjavascriptv0.9.0

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 18–223 runs

build_error

glibc

node 18–223 runs

build_error

Code

Verified usage

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

default loader

✓ module.exports = { module: { rules: [ { test: /\.ya?ml$/, use: 'yaml-loader' } ] } }

✗ module.exports = { module: { rules: [ { test: /\.ya?ml$/, loader: 'yaml-loader' } ] } }

When using options, the configuration must use `use` or `loader` with `options` object.

JavaScript import from YAML

✓ import config from './config.yaml';

✗ const config = require('./config.yaml');

ESM import works with Webpack's module bundling; require() may not work in all setups.

TypeScript import (type)

✓ import type { YAMLType } from 'yaml'; // not needed for loader

✗ import yaml from 'yaml'; // yaml is not directly imported by the loader user

The loader itself does not re-export yaml types; use the 'yaml' package directly if type access is needed.

Options with query parameter

✓ import data from './data.yaml?namespace=config';

Query parameters override options set in webpack.config.js.

CommonJS require

✓ const data = require('./data.yaml');

✗ const data = require('yaml-loader!./data.yaml');

Inline loader syntax is discouraged; use Webpack configuration instead.

Configures Webpack to import YAML files as JavaScript objects using yaml-loader.

// webpack.config.js module.exports = { module: { rules: [ { test: /\.ya?ml$/, use: 'yaml-loader', }, ], }, }; // app.js import config from './config.yaml'; console.log(config); // config.yaml server: port: 8080 host: localhost

Debug

Known issues

breakingDrop support for Webpack v4 (#61) and unsupported Node.js versions

fix

Upgrade to Webpack 5 and Node.js 20 or later.

affects: >=0.9.0

breakingOutput JavaScript source by default, rather than JSON (#27)

fix

Set `{ asJSON: true }` option if you need JSON output.

affects: >=0.7.0

breakingReplace `js-yaml` dependency with `yaml`

fix

Some YAML files parsed as valid by js-yaml may now be invalid; review your YAML files and update if needed.

affects: >=0.6.0

breakingDrop output JSON prettification

fix

Output is no longer multiline or tab-indented; if you need prettified JSON, chain another loader or use `asJSON` option and format yourself.

affects: >=0.6.0

deprecatedNode.js versions below 12.13 are no longer supported

fix

Upgrade Node.js to at least 12.13.

affects: >=0.8.0

gotchaOptions set in webpack.config.js via `options` object are superseded by query parameters (`?namespace=...`)

fix

Use either `options` in config or query parameters, not both, to avoid confusion.

affects: all

gotchaThe `asStream` option always outputs an array and ignores `namespace`

fix

Do not combine `asStream` with `namespace`; they are mutually exclusive.

affects: >=0.6.0

Errors

Common errors & fixes

Module parse failed: Unexpected token (1:2)

Webpack is trying to parse a YAML file without the yaml-loader configured.

fix

Add module rule in webpack.config.js: { test: /\.ya?ml$/, use: 'yaml-loader' }

Error: Cannot find module 'yaml'

The 'yaml' package is not installed.

fix

Run: npm install --save-dev yaml

Critical dependency: the request of a dependency is an expression

Using inline loader syntax like `require('yaml-loader!./file.yaml')` with dynamic path.

fix

Configure the loader in webpack.config.js and use static imports instead.

yaml-loader: options are not allowed for this loader (use 'use' instead of 'loader' with options)

Passing options with `loader` key directly instead of inside `use`.

fix

Use: { use: { loader: 'yaml-loader', options: { asJSON: true } } }

Upgrade

Version history

0.9.0latest on npm

Audit

Dependencies

webpackrequiredpeer dependency; loader is designed to work with Webpack 5+

yamlrequiredused internally for parsing YAML files

Agent activity

24 hits · last 30 days

node

OpenAI (training)

Resources

githubhttps://github.com/eemeli/yaml-loader ↗

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