The const keyword
The ES6 const
keyword is used to declare the read-only variables, that is, the variables whose value cannot be reassigned. Before ES6, the programmers usually used to prefix the variables that were supposed to be constant. For example, take a look at the following code:
var const_pi = 3.141; var r = 2; console.log(const_pi * r * r); //Output "12.564"
The value of pi
should always remain constant. Here, although we have prefixed it, there is still a chance that we might accidentally change its value somewhere in the program, as they're no native protection to the value of pi
. Prefixing is just not enough to keep the track of the constant variables.
Therefore, the const
keyword was introduced to provide a native protection to the ...
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