Jest Platform

    Tool for identifying modified files in a git/hg repository. Exports two functions:

    • returns a promise that resolves to an object with the changed files and repos.
    • findRepos returns a promise that resolves to a set of repositories contained in the specified path.

    You can read more about jest-changed-files in the readme file.

    jest-diff

    Tool for visualizing changes in data. Exports a function that compares two values of any type and returns a “pretty-printed” string illustrating the difference between the two arguments.

    Example

    1. const {diff} = require('jest-diff');
    2. const a = {a: {b: {c: 5}}};
    3. const b = {a: {b: {c: 6}}};
    5. const result = diff(a, b);
    7. // print diff
    8. console.log(result);

    Tool for extracting and parsing the comments at the top of a JavaScript file. Exports various functions to manipulate the data inside the comment block.

    jest-get-type

    Module that identifies the primitive type of any JavaScript value. Exports a function that returns a string with the type of the value passed as argument.

    Example

    1. const {getType} = require('jest-get-type');
    4. const nullValue = null;
    5. const undefinedValue = undefined;
    7. // prints 'array'
    8. console.log(getType(array));
    9. // prints 'null'
    10. console.log(getType(nullValue));
    11. console.log(getType(undefinedValue));

    Tool for validating configurations submitted by users. Exports a function that takes two arguments: the user’s configuration and an object containing an example configuration and other options. The return value is an object with two attributes:

    • hasDeprecationWarnings, a boolean indicating whether the submitted configuration has deprecation warnings,
    • isValid, a boolean indicating whether the configuration is correct or not.

    You can read more about jest-validate in the .

    jest-worker

    Module used for parallelization of tasks. Exports a class JestWorker that takes the path of Node.js module and lets you call the module’s exported methods as if they were class methods, returning a promise that resolves when the specified method finishes its execution in a forked process.

    Example

    1. module.exports = {
    3.     // long running CPU intensive task.
    4.   },
    5. };

    main.js

    You can read more about jest-worker in the readme file.

    Exports a function that converts any JavaScript value into a human-readable string. Supports all built-in JavaScript types out of the box and allows extension for application-specific types via user-defined plugins.

    1. const {format: prettyFormat} = require('pretty-format');
    3. const val = {object: {}};
    4. val.circularReference = val;
    5. val[Symbol('foo')] = 'foo';
    6. val.map = new Map([['prop', 'value']]);
    7. val.array = [-0, Infinity, NaN];
    9. console.log(prettyFormat(val));

    You can read more about pretty-format in the .