Creates and names a new constant. Like a variable created with let, a constant that is created with const is a container for a value, however constants cannot be reassigned once they are declared. Although it is noteworthy that for non-primitive data types like objects & arrays, their elements can still be changeable. So if a variable is assigned an array, you can still add or remove elements from the array but cannot reassign another array to it. Also unlike let, you cannot declare variables without value using const.
Constants have block-scope. This means that the constant only exists within the block that it is created within. A constant cannot be redeclared within a scope in which it already exists.
From the MDN entry: Declares a read-only named constant. Constants are block-scoped, much like variables defined using the 'let' statement. The value of a constant can't be changed through reassignment, and it can't be redeclared.
示例
相关参考
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console
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