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Assignment = = is the assignment operator. There's nothing much to say here. Abstract Equality == == is abstract equality - it will attempt to perform a type conversion before evaluating equalit...
Answer
#3: Post edited
by
Moshi
·
2021-07-28T05:36:51Z (over 3 years ago)
Added some headers to make it look nice
- `=` is the assignment operator. There's nothing much to say here.
- `==` is abstract equality - it will attempt to perform a type conversion before evaluating equality.
- E.g.
- ```javascript
- 1 == '1'
- 1 == true
- null == undefined
- ```
- Objects only compare equal if both sides *reference* the same object.
- Therefore, perhaps counterintuitively,
- ```
- var x = {};
- console.log(x == {}) // False
- ```
- `===` is strict equality - it checks that both have the same type and have the same value. The example above would not compare equal if it were using the strict equality operator.
- Note that `NaN` doesn't compare equal to anything, including `NaN`
- ```javascript
- NaN != NaN
- NaN !== NaN
- ```
Bonus: `Object.is`- `Object.is` is even stricter than `===`, requiring *exact* values.
- ```
- Object.is(+0, -0) // false
- ```
- It is useful for `NaN` though, as `Object.is(NaN, NaN)` returns true.
- ## Assignment `=`
- `=` is the assignment operator. There's nothing much to say here.
- ## Abstract Equality `==`
- `==` is abstract equality - it will attempt to perform a type conversion before evaluating equality.
- E.g.
- ```javascript
- 1 == '1'
- 1 == true
- null == undefined
- ```
- Objects only compare equal if both sides *reference* the same object.
- Therefore, perhaps counterintuitively,
- ```
- var x = {};
- console.log(x == {}) // False
- ```
- ## Strict Equality `===`
- `===` is strict equality - it checks that both have the same type and have the same value. The example above would not compare equal if it were using the strict equality operator.
- Note that `NaN` doesn't compare equal to anything, including `NaN`
- ```javascript
- NaN != NaN
- NaN !== NaN
- ```
- ## Bonus: `Object.is`
- `Object.is` is even stricter than `===`, requiring *exact* values.
- ```
- Object.is(+0, -0) // false
- ```
- It is useful for `NaN` though, as `Object.is(NaN, NaN)` returns true.
#2: Post edited
by
Moshi
·
2021-07-28T05:34:07Z (over 3 years ago)
`=` is the assignment operator.- `==` is abstract equality - it will attempt to perform a type conversion before evaluating equality.
- E.g.
```- 1 == '1'
- 1 == true
- null == undefined
- ```
`===` is strict equality - it checks that both of them are the same type and have the same value.
- `=` is the assignment operator. There's nothing much to say here.
- `==` is abstract equality - it will attempt to perform a type conversion before evaluating equality.
- E.g.
- ```javascript
- 1 == '1'
- 1 == true
- null == undefined
- ```
- Objects only compare equal if both sides *reference* the same object.
- Therefore, perhaps counterintuitively,
- ```
- var x = {};
- console.log(x == {}) // False
- ```
- `===` is strict equality - it checks that both have the same type and have the same value. The example above would not compare equal if it were using the strict equality operator.
- Note that `NaN` doesn't compare equal to anything, including `NaN`
- ```javascript
- NaN != NaN
- NaN !== NaN
- ```
- Bonus: `Object.is`
- `Object.is` is even stricter than `===`, requiring *exact* values.
- ```
- Object.is(+0, -0) // false
- ```
- It is useful for `NaN` though, as `Object.is(NaN, NaN)` returns true.
#1: Initial revision
by
Moshi
·
2021-07-28T05:25:22Z (over 3 years ago)
`=` is the assignment operator. `==` is abstract equality - it will attempt to perform a type conversion before evaluating equality. E.g. ``` 1 == '1' 1 == true null == undefined ``` `===` is strict equality - it checks that both of them are the same type and have the same value.