Javascript string object readonly?

Question

a=new String("Hello");

a[0]==="H" //true
a[0]="J"
a[0]==="J" //false
a[0]==="H" //true

Does this mean I can only use Strings as arrays of char's by .split("") and then .join("")?

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ANSWER: Yes, in Javascript strings are readonly (aka immutable) This question is answered here at:

• Are JavaScript strings immutable? Do I need a "string builder" in JavaScript?
• What does immutable mean?

Answer 1

Strings are immutable, so yes. a should be reassigned if you want to change the string. You can also use slice: a = 'j'+a.slice(1), or a replace: a = a.replace(/^h/i,'j').

You could create a custom mutable String object, something like this experiment (esp. see method replaceCharAt).

Answer 2

Thats correct.

You can of course build a function to handle this for you.

See this SO Post for different examples of this:

How do I replace a character at a particular index in JavaScript?