https://github.com/andywer/deep-assert
🔍 Better deep-equals comparison, supporting custom property assertions and pretty diffs.
https://github.com/andywer/deep-assert
assertions deep-equals diff javascript json json-diff nodejs testing typescript
Last synced: 6 months ago
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🔍 Better deep-equals comparison, supporting custom property assertions and pretty diffs.
- Host: GitHub
- URL: https://github.com/andywer/deep-assert
- Owner: andywer
- License: mit
- Created: 2019-04-27T13:03:30.000Z (almost 7 years ago)
- Default Branch: master
- Last Pushed: 2022-01-12T10:47:49.000Z (about 4 years ago)
- Last Synced: 2025-04-09T21:07:58.639Z (11 months ago)
- Topics: assertions, deep-equals, diff, javascript, json, json-diff, nodejs, testing, typescript
- Language: TypeScript
- Homepage:
- Size: 189 KB
- Stars: 3
- Watchers: 2
- Forks: 2
- Open Issues: 0
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
# deep-assert
[](https://travis-ci.org/andywer/deep-assert)
[](https://www.npmjs.com/package/deep-assert)
The most developer-friendly way to write assertions for large or complicated objects and arrays.
* Use `any()` and `satisfies()` property matchers
* Short, but precise diffs, even for large nested objects
* Works with objects, arrays, dates, buffers, and more
* Write custom property assertions
* Zero dependencies
## Installation
```
npm install deep-assert
```
## Usage
### Basic
Let's say we want to check if an array of user objects matches our expectation, but we don't know what the `id` is gonna be, since it's a random ID. It's easy, using `any()`.
```js
import * as assert from "assert-deep"
assert.deepEquals(
// Actual value:
{
id: Math.random(),
name: "John Smith",
meta: {
isActive: true,
lastLogin: new Date("2019-04-29T12:31:00")
}
},
// Expectation:
{
id: assert.any(),
name: "John Smith",
meta: {
isActive: true,
lastLogin: new Date("2019-04-29T12:31:00")
}
}
])
```
### Custom assertions
Let's try the previous use case again, but this time we check that the `id` is a valid UUIDv4. We use the `satisfies()` helper function to create a custom assertion to be used within the object expectation.
```js
import * as assert from "assert-deep"
const assertPositiveNumber = () => assert.satisfies(value => typeof value === "number" && value > 0)
assert.deepEquals(
// Actual value:
{
id: Math.random(),
name: "John Smith",
meta: {
isActive: true,
lastLogin: new Date("2019-04-29T12:31:00")
}
},
// Expectation:
{
id: assertPositiveNumber(),
name: "John Smith",
meta: {
isActive: true,
lastLogin: new Date("2019-04-29T12:31:00")
}
}
])
```
### Spreading any()
Normally `deepEquals()` will fail if there are properties on the tested object that don't exist on the expectation. We can use `any()` with the object spread operator to allow additional properties to be present.
`deepEquals()` will then only check the expected properties and ignore all other ones.
```js
import * as assert from "assert-deep"
assert.deepEquals(
// Actual value:
{
id: Math.random(),
name: "John Smith",
meta: {
isActive: true,
lastLogin: new Date("2019-04-29T12:31:00")
}
},
// Expectation:
{
id: assert.any(),
name: "John Smith",
...assert.any()
}
])
```
### Recursive objects
You can call `deepEquals()` in a custom `satisfies()` as well. This way you can easily test recursive data structures, for instance.
```js
import * as assert from "assert-deep"
const actual = { foo: {} }
actual.foo.parent = actual.foo
assert.deepEquals(actual, {
foo: assert.satisfies(foo => assert.deepEquals(foo, { parent: foo }))
})
```
## License
MIT