locutus
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Locutus other languages' standard libraries to JavaScript for fun and educational purposes
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JavaScript
export function count_chars(str, mode = 0) {
// discuss at: https://locutus.io/php/count_chars/
// parity verified: PHP 8.3
// original by: Ates Goral (https://magnetiq.com)
// improved by: Jack
// bugfixed by: Onno Marsman (https://twitter.com/onnomarsman)
// bugfixed by: Kevin van Zonneveld (https://kvz.io)
// input by: Brett Zamir (https://brett-zamir.me)
// revised by: Theriault (https://github.com/Theriault)
// example 1: count_chars("Hello World!", 3)
// returns 1: " !HWdelor"
// example 2: count_chars("Hello World!", 1)
// returns 2: {32:1,33:1,72:1,87:1,100:1,101:1,108:3,111:2,114:1}
const result = {};
let i = 0;
const groupedChars = ('' + str)
.split('')
.sort()
.join('')
.match(/(.)\1*/g) || [];
if (mode === 3) {
let presentChars = '';
for (i = 0; i !== groupedChars.length; i += 1) {
const grouped = groupedChars[i];
if (grouped === undefined) {
continue;
}
presentChars += grouped.slice(0, 1);
}
return presentChars;
}
if ((mode & 1) === 0) {
for (i = 0; i !== 256; i++) {
result[i] = 0;
}
}
if (mode === 2 || mode === 4) {
for (i = 0; i !== groupedChars.length; i += 1) {
const grouped = groupedChars[i];
if (grouped === undefined) {
continue;
}
delete result[grouped.charCodeAt(0)];
}
if (mode === 4) {
let absentChars = '';
for (const key of Object.keys(result)) {
absentChars += String.fromCharCode(Number(key));
}
return absentChars;
}
for (const key of Object.keys(result)) {
result[key] = 0;
}
}
else {
for (i = 0; i !== groupedChars.length; i += 1) {
const grouped = groupedChars[i];
if (grouped === undefined) {
continue;
}
result[grouped.charCodeAt(0)] = grouped.length;
}
}
return result;
}