CODEWITHSUNDEEP
javascriptstring
Nitish Jain
Nitish Jain

Reputation: 734

How the JavaScript String is a set of "elements" of 16-bit unsigned integer values?

From the MDN

JavaScript's String type is used to represent textual data. It is a set of "elements" of 16-bit unsigned integer values. Each element in the String occupies a position in the String. The first element is at index 0, the next at index 1, and so on. The length of a String is the number of elements in it. You can create strings using string literals or string objects.

How the JavaScript String type is a set of "elements" of 16-bit unsigned integer values, why not 8-bit unsigned integer values?

Upvotes: 0

Views: 1296

Answers (2)

Bergi
Bergi

Reputation: 665130

Looking at the full spec text helps here:

The String type is the set of all ordered sequences of zero or more 16-bit unsigned integer values (“elements”) up to a maximum length of 253-1 elements. The String type is generally used to represent textual data in a running ECMAScript program, in which case each element in the String is treated as a UTF-16 code unit value.

Similar can be found in the ES5.1 spec.

Why not 8-bit unsigned integer values? That would have been equally possible, using UTF-8. But it wasn't done, and that's just how it is now.

Upvotes: 3

Jack A.
Jack A.

Reputation: 4453

Because EcmaScript is written using Unicode, a.k.a. UTF-16:

ECMAScript source text is assumed to be a sequence of 16-bit code units for the purposes of this specification.

http://www.ecma-international.org/ecma-262/5.1/#sec-6

Upvotes: 0

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