Problems inserting charCodes into array

Question

This is a bit maddening. New to javascript and I haven't coded in ages. I am looking to convert a string of characters into their charCodes and dump them into an array. This is the current code:

function fillArray(str) {
var arr=[];

  for (var i = 0; i < str.length; i++) {

    arr.push(str.charCodeAt(str.charAt(i)));
  }

  return arr;
}

What ends up happening is if I sent it a string like "abcd", it will return [97,97,97,97]. Even though the charAt(i) should be iterating through, the array only seems to be formed by looking at the first character in the string only. What am I missing?

T.J. Crowder · Accepted Answer · 2016-12-07 14:51:32Z

2

charCodeAt takes the index of the character you want, not the actual character; so just remove the charAt part:

arr.push(str.charCodeAt(i));

answered Dec 7, 2016 at 14:51

T.J. Crowder

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2 Comments

Mahi Over a year ago

but why he is getting 97 all time

Pointy Over a year ago

@Mahi because he's passing the return value from .charAt() as the index to be used by .charCodeAt(). It'll generally evaluate to NaN, which charCodeAt() accepts as equivalent to 0.

Michał Perłakowski · Accepted Answer · 2016-12-07 14:56:17Z

1

As T.J. Crowder pointed out, String.prototype.charCodeAt() takes an index as a parameter. The reason you're getting 97 all the time is (from MDN):

if it [the parameter] is not a number, it defaults to 0.

So it always takes the first letter (with index 0), which is "a" and its char code is 97.

answered Dec 7, 2016 at 14:56

Michał Perłakowski

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Comments

kevin ternet · Accepted Answer · 2016-12-07 17:09:21Z

0

You could split your string in an array (dumping) and map each character with its ascci code (transfarmation expected). This way, you would write it shortly in JS :

var fillArray = str => str.split("").map(x => x.charCodeAt(0));
console.log(fillArray("bonjour le monde"));

answered Dec 7, 2016 at 17:09

kevin ternet

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