62 lines
1.9 KiB
Markdown
62 lines
1.9 KiB
Markdown
# Suggest using `toBe()` for primitive literals (`prefer-to-be`)
|
|
|
|
💼 This rule is enabled in the 🎨 `style`
|
|
[config](https://github.com/jest-community/eslint-plugin-jest/blob/main/README.md#shareable-configurations).
|
|
|
|
🔧 This rule is automatically fixable by the
|
|
[`--fix` CLI option](https://eslint.org/docs/latest/user-guide/command-line-interface#--fix).
|
|
|
|
<!-- end auto-generated rule header -->
|
|
|
|
When asserting against primitive literals such as numbers and strings, the
|
|
equality matchers all operate the same, but read slightly differently in code.
|
|
|
|
This rule recommends using the `toBe` matcher in these situations, as it forms
|
|
the most grammatically natural sentence. For `null`, `undefined`, and `NaN` this
|
|
rule recommends using their specific `toBe` matchers, as they give better error
|
|
messages as well.
|
|
|
|
## Rule details
|
|
|
|
This rule triggers a warning if `toEqual()` or `toStrictEqual()` are used to
|
|
assert a primitive literal value such as numbers, strings, and booleans.
|
|
|
|
The following patterns are considered warnings:
|
|
|
|
```js
|
|
expect(value).not.toEqual(5);
|
|
expect(getMessage()).toStrictEqual('hello world');
|
|
expect(loadMessage()).resolves.toEqual('hello world');
|
|
```
|
|
|
|
The following pattern is not warning:
|
|
|
|
```js
|
|
expect(value).not.toBe(5);
|
|
expect(getMessage()).toBe('hello world');
|
|
expect(loadMessage()).resolves.toBe('hello world');
|
|
expect(didError).not.toBe(true);
|
|
|
|
expect(catchError()).toStrictEqual({ message: 'oh noes!' });
|
|
```
|
|
|
|
For `null`, `undefined`, and `NaN`, this rule triggers a warning if `toBe` is
|
|
used to assert against those literal values instead of their more specific
|
|
`toBe` counterparts:
|
|
|
|
```js
|
|
expect(value).not.toBe(undefined);
|
|
expect(getMessage()).toBe(null);
|
|
expect(countMessages()).resolves.not.toBe(NaN);
|
|
```
|
|
|
|
The following pattern is not warning:
|
|
|
|
```js
|
|
expect(value).toBeDefined();
|
|
expect(getMessage()).toBeNull();
|
|
expect(countMessages()).resolves.not.toBeNaN();
|
|
|
|
expect(catchError()).toStrictEqual({ message: undefined });
|
|
```
|