jest-webpack-alias

jest-webpack-alias

Preprocessor for Jest that is able to resolve require() statements using webpack aliases.

See also transform-jest-deps.

Install

npm install --save-dev jest-webpack-alias

Setup

File __tests__/preprocessor.js:

var babelJest = require('babel-jest');
var webpackAlias = require('jest-webpack-alias');

module.exports = {
  process: function(src, filename) {
    if (filename.indexOf('node_modules') === -1) {
      src = babelJest.process(src, filename);
      src = webpackAlias.process(src, filename);
    }
    return src;
  }
};

File package.json:

{
  ...
  "jest": {
    ...
    "scriptPreprocessor": "<rootDir>/__tests__/preprocessor.js",
  },
  "jest-webpack-alias": {
    "profile": "dev"
  }
}

Manual package resolution

Code like this will not work, because an AST parser is not smart enough to evaluate variables into strings.

var moduleName = 'myModName';
var computed = require(moduleName);

It can be rewritten like this, using the resolve function:

var resolve = require('jest-webpack-alias').resolve;
var moduleName = 'myModName';
var computed = require(resolve(moduleName, __filename));

package.json options

• jest-webpack-alias.configFile: Optional, default is "webpack.config.js". If provided, this should be a path fragment relative to your package.json file. Example: "webpack/config.dev.js".

• jest-webpack-alias.profile: Optional. If provided, will expect your webpack config to be an array of profiles, and will match against the name field of each to choose a webpack config that applies to your Jest tests. See https://github.com/webpack/webpack/tree/master/examples/multi-compiler for an example of this kind of setup.

Missing features

This module does not yet support:

• resolve.alias settings whose values are absolute paths

License

MIT