A mocking library for unit testing in JavaScript and TypeScript.

Why?

Using Mock On! helps prevent copy-paste unit testing. I find that unit tests with copy-pasted dummy data, often use the same values over and over. This can be problematic if there is any bleeding values between tests and really doesn't test the whole range of a piece of code.

This:

interface Shape {
  id: string;
  url: string;
}
const testShapes = [
    {
        id: `shapeid-0`,
        url: "http://www.example.com/image.jpg"
    },
    {
        id: `shapeid-1`,
        url: "http://www.example.com/image.jpg"
    },
    {
        id: `shapeid-2`,
        url: "http://www.example.com/image.jpg"
    },
    {
        id: `shapeid-3`,
        url: "http://www.example.com/image.jpg"
    },
    {
        id: `shapeid-4`,
        url: "http://www.example.com/image.jpg"
    }
];

Becomes:

import { mockArrayOf, mockString, mockUrl } from "mock-on";

interface Shape {
  id: string;
  url: string;
}

const testShapes = mockArrayOf((): Shape => ({ id: mockString(), url: mockUrl() });

Mock Generators

Basic

mockInt

Generates a random integer.

Property Name	Type	Required	Default	Description
min	number	No	0	minimum integer value
max	number	No	100	maximum integer value

Example

Generate a random integer value between 0 and 100

const myInt = mockInt();

Example

Generate a random integer value between two values

const myInt = mockInt({ min: 10, max: 20 });

mockBoolean

Generates a random boolean.

Property Name	Type	Required	Default	Description
-	-	-	-	-

Example

Generate a random boolean value.

const myBoolean = mockBoolean();

mockString

Generates a random string. By default this function will generate a string between ascii values 48-57 (numbers), 65-90 (A-Z), and 97-122 (a-z).

Property Name	Type	Required	Default	Description
maxLength	number	No	30
maximum string length
minLength	number	No	1
minimum string length
charCodeStart	`number	number[]`	[48,65,97] Single

charCode value or multiple starts to build ranges.  **Must Correspond
with `charCodeEnd`** |

| charCodeEnd | number | number[] | [48,65,97] Single charCode value or multiple ends to build ranges. Must Correspond with charCodeStart | | charSet | string[] | No | - | an array of characters to use. If this value is passed it will take prescedence over charCodeStart and charCodeEnd values |

Example

Generate a random string value that is between 1 and 30 characters long.

const myString = mockString();

Example

Generate a random string value that is between two a minimum and maximum length.

const myString = mockString({ maxLength: 100, minLength: 80 });

Example

Generate a random string value of only lowercase letters.

const myString = mockString({ charCodeStart: 97, charCodeEnd: 122 });
// or
const myString = mockString({ charCodeStart: [ 97 ], charCodeEnd: [ 122 ] });

Example

Generate a random string value of lowercase letters and punctuation.

const myString = mockString({
  charCodeStart: [97, 33, 44, 46, 63],
  charCodeEnd: [122, 33, 44, 46, 63],
});

Example

Generate a random string value of out of a set of characters.

const myString = mockString({ charSet: ['a','b','c','d','-'] });

Less Basic

mockArrayOf

Generates an Array of a single value that is created via the create argument.

Property Name	Type	Required	Default	Description
create	(index?: number) => Type	Yes	-	function that creates an instance for the array
maxLength	number	No	30	maximum array length
minLength	number	No	1	minimum array length
length	number	No	-	specific array length. If specified this overrides the minLength/maxLength values

Example

Generate an array of a given type between 3 and 5 items long.

interface MyObject {
  id: string;
  url: string;
}

const arrayOfMyObjects: MyObject[] = mockArrayOf(
  (index: number): MyObject => ({
    id: `id-${index}`, url: mockUrl(),
  }),
  {
    maxLength: 5, minLength: 3,
  },
);

mockHexColor

Generates a random six character hex color string

Property Name	Type	Required	Default	Description
leadingChar	string	No	""	Prepends to beginning of the returned hex string

Example

Generate a random hex color.

const myHexColor = mockHexColor();

mockIntArray

Generates a random array of integers

Property Name	Type	Required	Default	Description
min	number	No	0	minimum integer value
max	number	No	100	maximum integer value
maxLength	number	No	30	maximum array length
minLength	number	No	1	minimum array length
length	number	No	-	specific array length. If specified this overrides the minLength/maxLength values
unique	boolean	No	false	true if all integers should be unique

Example

Generate a random int array of values between 0 and 10.

// 0 is min default so it is unnecessary to pass that here
const myIntArray = mockIntArray({min: 0, max: 10});

Example

Generate a random int array of length 100 values between 0 and 100 (default int values).

const myIntArray = mockIntArray({length: 100});

mockItem

documentation coming soon...

mockPath

documentation coming soon...

mockSegmentedString

documentation coming soon...

mockStringArray

documentation coming soon...

mockSubset

documentation coming soon...

mockUrl

documentation coming soon...

Utilities

getPowerSet

documentation coming soon...

isPrimitive

documentation coming soon...

maybeUndefined

documentation coming soon...

shuffle

documentation coming soon...