What is === in javascript example?
The strict equality operator ( The strict equality operators ( The most notable difference between this operator and the equality ( Comparing operands of different types
Comparing objects
Specifications
Browser compatibilityBCD tables only load in the browser See alsoJavaScript provides three different value-comparison operations: Which operation you choose depends on what sort of comparison you are looking to perform. Briefly: They correspond to three of four equality algorithms in JavaScript: Note that the distinction between these all have to do with their handling of primitives; none of them compares whether the parameters are conceptually similar in structure. For any non-primitive objects Strict equality compares two values for equality. Neither value is implicitly converted to some other value before being compared. If the values have different types, the values are considered unequal. If the values have the same type, are not numbers, and have the same
value, they're considered equal. Finally, if both values are numbers, they're considered equal if they're both not Strict equality is almost always the correct comparison operation to use. For all values except numbers, it uses the obvious semantics: a value is only equal to itself. For numbers it uses slightly different semantics to gloss over two different edge cases. The first is that floating
point zero is either positively or negatively signed. This is useful in representing certain mathematical solutions, but as most situations don't care about the difference between Besides
Loose equality using ==Loose equality is symmetric:
Traditionally, and according to ECMAScript, all primitives and objects are loosely unequal to
In most cases, using loose equality is discouraged. The result of a comparison using strict equality is easier to predict, and may evaluate more quickly due to the lack of type coercion. The following example demonstrates loose equality comparisons involving the number primitive
Loose equality is only used by the Same-value equality using Object.is()Same-value equality determines whether two values are functionally identical in all contexts. (This use case demonstrates an instance of the Liskov substitution principle.) One instance occurs when an attempt is made to mutate an immutable property:
Same-value equality is provided by the Same-value-zero equalitySimilar to same-value equality, but +0 and -0 are considered equal. Same-value-zero equality is not exposed as a JavaScript API, but can be implemented with custom code:
Same-value-zero only differs from strict equality by treating Comparing equality methodsPeople often compare double equals and triple equals by saying one is an "enhanced" version of the other. For example, double equals could be said as an extended version of
triple equals, because the former does everything that the latter does, but with type conversion on its operands — for example, However, this way of thinking implies that the equality comparisons form a one-dimensional "spectrum" where "totally strict" lies on one end and "totally
loose" lies on the other. This model falls short with When to use Object.is() versus triple equalsIn general, the only time
Here's a non-exhaustive list of built-in methods and operators that might cause a distinction between - (unary negation)Consider the following example:
If Math.atan2 ,
Math.ceil , Math.pow , Math.round In some cases, it's possible for a Math.floor , Math.max , Math.min ,
Math.sin , Math.sqrt , Math.tan It's possible to get a ~ , << , >>
Each of these operators uses the ToInt32 algorithm internally. Since there is only one representation for 0 in the internal 32-bit integer type, Relying on Caveat: Object.is() and NaNThe
See alsoWhat is === in JavaScript?The strict equality operator ( === ) checks whether its two operands are equal, returning a Boolean result. Unlike the equality operator, the strict equality operator always considers operands of different types to be different.
What is === and == in JavaScript?The main difference between the == and === operator in javascript is that the == operator does the type conversion of the operands before comparison, whereas the === operator compares the values as well as the data types of the operands.
What is triple === in JavaScript?JavaScript provides three different value-comparison operations: === — strict equality (triple equals) == — loose equality (double equals)
What does == === mean?The === operator means "is exactly equal to," matching by both value and data type. The == operator means "is equal to," matching by value only.
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