Skip to content

zirkelc/snapshot-serializers

Folders and files

NameName
Last commit message
Last commit date

Latest commit

Dec 18, 2024
ce82af0 · Dec 18, 2024

History

18 Commits
Nov 12, 2024
Dec 18, 2024
Nov 12, 2024
Dec 18, 2024
Dec 18, 2024
Nov 12, 2024
Nov 12, 2024
Nov 12, 2024
Dec 18, 2024
Dec 13, 2024
Dec 18, 2024
Dec 13, 2024
Nov 12, 2024
Nov 12, 2024

Repository files navigation

CI npm npm

Snapshot Serializers

A collection of snapshot serializers for Jest and Vitest to help manage dynamic values in your test snapshots.

Installation

npm install snapshot-serializers

Usage

Snapshot serializers must be added by using expect.addSnapshotSerializer API:

import { replaceProperty } from 'snapshot-serializers';

expect.addSnapshotSerializer(replaceProperty({ property: 'foo' }));

Replace Properties

Replace dynamic properties like auto-generated IDs or timestamps with placeholders in your snapshots:

import { replaceProperty } from 'snapshot-serializers';

// Replace single property with default placeholder '[SNAPSHOT_PLACEHOLDER]'
expect.addSnapshotSerializer(replaceProperty({ property: 'id' }));

// Replace multiple properties with custom placeholder
expect.addSnapshotSerializer(
  replaceProperty({
    property: ['createdAt', 'updatedAt'],
    placeholder: '[TIMESTAMP]'
  })
);

// Replace properties matching a pattern
expect.addSnapshotSerializer(
  replaceProperty({
    property: /^date/,
    placeholder: '[DATE]'
  })
);

test('user data snapshot', () => {
  const user = {
    id: '123e4567-e89b-12d3-a456-426614174000',
    name: 'John Doe',
    createdAt: '2024-03-20T12:00:00Z',
    updatedAt: '2024-03-21T15:30:00Z',
    dateJoined: '2024-03-20',
    dateLastLogin: '2024-03-21'
  };
  expect(user).toMatchInlineSnapshot(`
    {
      "id": "[SNAPSHOT_PLACEHOLDER]",
      "name": "John Doe",
      "createdAt": "[TIMESTAMP]",
      "updatedAt": "[TIMESTAMP]",
      "dateJoined": "[DATE]",
      "dateLastLogin": "[DATE]"
    }
  `);
});

Remove Properties

Remove properties that shouldn't be included in snapshots:

import { removeProperty } from 'snapshot-serializers';

// Remove single property
expect.addSnapshotSerializer(removeProperty({ property: 'password' }));

// Remove multiple properties
expect.addSnapshotSerializer(
  removeProperty({ property: ['password', 'secretKey', 'token'] })
);

// Remove properties matching a pattern
expect.addSnapshotSerializer(
  removeProperty({ property: /^secret/ })
);

test('user data without sensitive info', () => {
  const user = {
    id: '123',
    email: 'john@example.com',
    password: 'secret123',
    secretKey: 'abc123',
    secretToken: 'xyz789',
    token: 'jwt-token'
  };
  expect(user).toMatchInlineSnapshot(`
    {
      "id": "123",
      "email": "john@example.com"
    }
  `);
});

Type Safety

Provide a type argument to the replaceProperty and removeProperty functions to get type safety for your properties:

import { replaceProperty, removeProperty } from 'snapshot-serializers';

type User = {
  id: string;
  name: string;
  createdAt: string;
};

expect.addSnapshotSerializer(
  // type of property is "id" | "name" | "createdAt"
  replaceProperty<User>({ property: 'id' })
);

expect.addSnapshotSerializer(
  // "invalid" is not assignable to type '"id" | "name" | "createdAt"
  removeProperty<User>({ property: 'invalid' })
);

API

replaceProperty<T>(options)

Creates a serializer that replaces specific property values with placeholders.

  • options.property: The property to replace. Can be:
    • A single property name
    • An array of property names
    • A RegExp pattern to match multiple properties
  • options.placeholder: (Optional) Custom placeholder text. Defaults to [SNAPSHOT_PLACEHOLDER]

removeProperty<T>(options)

Creates a serializer that removes specific properties from the snapshot.

  • options.property: The property to remove. Can be:
    • A single property name
    • An array of property names
    • A RegExp pattern to match multiple properties

License

MIT