locutus/esm/php/strings/str_word_count.js

Locutus other languages' standard libraries to JavaScript for fun and educational purposes

import { ctype_alpha as ctypeAlpha } from "../ctype/ctype_alpha.js";
export function str_word_count(str, format, charlist) {
    //  discuss at: https://locutus.io/php/str_word_count/
    // original by: Ole Vrijenhoek
    // bugfixed by: Kevin van Zonneveld (https://kvz.io)
    // bugfixed by: Brett Zamir (https://brett-zamir.me)
    // bugfixed by: Brett Zamir (https://brett-zamir.me)
    //    input by: Bug?
    // improved by: Brett Zamir (https://brett-zamir.me)
    //   example 1: str_word_count("Hello fri3nd, you're\r\n       looking          good today!", 1)
    //   returns 1: ['Hello', 'fri', 'nd', "you're", 'looking', 'good', 'today']
    //   example 2: str_word_count("Hello fri3nd, you're\r\n       looking          good today!", 2)
    //   returns 2: {0: 'Hello', 6: 'fri', 10: 'nd', 14: "you're", 29: 'looking', 46: 'good', 51: 'today'}
    //   example 3: str_word_count("Hello fri3nd, you're\r\n       looking          good today!", 1, '\u00e0\u00e1\u00e3\u00e73')
    //   returns 3: ['Hello', 'fri3nd', "you're", 'looking', 'good', 'today']
    //   example 4: str_word_count('hey', 2)
    //   returns 4: {0: 'hey'}
    const len = str.length;
    const cl = charlist?.length ?? 0;
    let chr = '';
    let tmpStr = '';
    let c = '';
    const wArr = [];
    let wC = 0;
    const assoc = {};
    let aC = 0;
    let reg = null;
    let match = false;
    const _pregQuote = function (value) {
        return (value + '').replace(/([\\.+*?[^\]$(){}=!<>|:])/g, '\\$1');
    };
    const _getWholeChar = function (value, index) {
        // Use for rare cases of non-BMP characters
        const code = value.charCodeAt(index);
        if (code < 0xd800 || code > 0xdfff) {
            return value.charAt(index);
        }
        if (code >= 0xd800 && code <= 0xdbff) {
            // High surrogate (could change last hex to 0xDB7F to treat high private surrogates as single
            // characters)
            if (value.length <= index + 1) {
                throw new Error('High surrogate without following low surrogate');
            }
            const next = value.charCodeAt(index + 1);
            if (next < 0xdc00 || next > 0xdfff) {
                throw new Error('High surrogate without following low surrogate');
            }
            return value.charAt(index) + value.charAt(index + 1);
        }
        // Low surrogate (0xDC00 <= code && code <= 0xDFFF)
        if (index === 0) {
            throw new Error('Low surrogate without preceding high surrogate');
        }
        const prev = value.charCodeAt(index - 1);
        if (prev < 0xd800 || prev > 0xdbff) {
            // (could change last hex to 0xDB7F to treat high private surrogates as single characters)
            throw new Error('Low surrogate without preceding high surrogate');
        }
        // We can pass over low surrogates now as the second component in a pair which we have already
        // processed
        return false;
    };
    if (cl && typeof charlist === 'string') {
        const firstChar = _getWholeChar(charlist, 0);
        let pattern = '^(' + _pregQuote(firstChar === false ? '' : firstChar);
        for (let i = 1; i < cl; i++) {
            const wholeChar = _getWholeChar(charlist, i);
            if (wholeChar === false) {
                continue;
            }
            chr = wholeChar;
            pattern += '|' + _pregQuote(chr);
        }
        pattern += ')$';
        reg = new RegExp(pattern);
    }
    for (let i = 0; i < len; i++) {
        const wholeChar = _getWholeChar(str, i);
        if (wholeChar === false) {
            continue;
        }
        c = wholeChar;
        // No hyphen at beginning or end unless allowed in charlist (or locale)
        // No apostrophe at beginning unless allowed in charlist (or locale)
        // @todo: Make this more readable
        match =
            ctypeAlpha(c) ||
                (reg !== null && reg.test(c)) ||
                (i !== 0 && i !== len - 1 && c === '-') ||
                (i !== 0 && c === "'");
        if (match) {
            if (tmpStr === '' && format === 2) {
                aC = i;
            }
            tmpStr = tmpStr + c;
        }
        if (i === len - 1 || (!match && tmpStr !== '')) {
            if (format !== 2) {
                wArr.push(tmpStr);
            }
            else {
                assoc[aC] = tmpStr;
            }
            tmpStr = '';
            wC++;
        }
    }
    if (!format) {
        return wC;
    }
    else if (format === 1) {
        return wArr;
    }
    else if (format === 2) {
        return assoc;
    }
    throw new Error('You have supplied an incorrect format');
}