ToPrimitive(String): Works the same, but invokes obj.toString() before obj.valueOf(). JavaScript has different built-in methods to convert or cast a string into a number.If the result is primitive, return that result. ToPrimitive(Number): To convert an object obj to a primitive, invoke obj.valueOf().If index is out of range, charCodeAt () returns NaN. Return value A number representing the UTF-16 code unit value of the character at the given index. If index is not a number, it defaults to 0. However, + uses the internal ToPrimitive(Number) operation (except for dates ), while String() uses ToPrimitive(String). Syntax charCodeAt(index) Parameters index An integer greater than or equal to 0 and less than the length of the string. The following table explains how ToString() operates on primitives.īoth approaches first convert an object to a primitive, before converting that primitive to string. “Internal” means: a function specified by the ECMAScript 5.1 (§9.8) that isn’t accessible to the language itself. But how do they actually do that? It turns out that they do it in slightly different ways, but usually arrive at the same result.īoth approaches use the internal ToString() operation to convert primitives to string. Until now you have heard that + and String() convert their “argument” to string. The latter is hardly ever useful in JavaScript, which is why you can usually forget about String as a constructor and concentrate on its role as converting to string.Ī minor difference between ""+value and String(value) The constructor produces an instance of the type String (an object). The parseInt function in Javascript takes a string and converts. The function produces, as promised, a string (a primitive ). A string in a Javascript program can be converted into a number using the parseInt() function. However, function and constructor produce completely different results: The only problem is that this function call will confuse some people, especially those coming from Java, because String is also a constructor. ![]()
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