paknevis/src/paknevis.ts

Paknevis.js is a persian text formatter tool.

import { defaultBadWords } from './data/badWords';

/**
 * Base class of Paknevis.js
 * @class
 */
export class Paknevis {

    /**
     * This function normalise strings to improve detection of banned words.
     * @param {string} text your text
     * @returns {string}
     */
    private static normalise(text: string): string {
        return text
        .replace(/[\u200c\u200d\u200e\u200f\u202a-\u202e\s‌‏‍ ]/gm, '')
        .replace(/[,،؛:!؟?"'«»‹›()\[\]{}\-_/\*~^@#$%=\|`']/gm, '')
        .replace(/ك/gm, 'ک')
        .replace(/[۰-۹]/gm, d => String.fromCharCode(d.charCodeAt(0) - 1728))
        .replace(/[٠-٩]/gm, d => String.fromCharCode(d.charCodeAt(0) - 1632))
        .replace(/[\u064b-\u0652\u0670]/gm, '')
        .replace(/ـ/gm, '')
        .replace(/[يى]/gm, 'ی')
        .replace(/[ثص]/gm, 'س')
        .replace(/[زذضظ]/gm, 'ز')
        .replace(/ح/gm, 'ه')
        .replace(/[تط]/gm, 'ت')
        .replace(/[عءئ]/gm, 'ا')
        .replace(/[ؤو]/gm, 'و')
        .replace(/[^آابپتثجچحخدذرزسشصضطظعغفقکگلمنوهی0-9]/gm, '').toLocaleLowerCase('fa');
    };

    /**
     * This function checks if text contains any filtered word.good for just checking.
     * @param {string} text input text
     * @param {string[]} [extraWords] use this to add any extra words in array.
     * @returns {boolean} 
     */
    static hasBadWords(text: string, extraWords: string[] = []): boolean {
        let arrayOfWords: string[] = Array.from(new Set([...defaultBadWords, ...extraWords]));
        return arrayOfWords.some(word => this.normalise(text).includes(word))
    }


    /**
     * This function censores banned words.note that it could not find words in some scenarios.
     * @param {string} text input text
     * @param {string} [censorChar] good for masking banned word. defualt is empty.
     * @param {string[]} [extraWords] use this to add any extra words in array.
     * @returns {string}
     */
    static censor(text: string, censorChar: string = "", extraWords: string[] = []): string {
        const allWords: string[] = Array.from(new Set([...defaultBadWords, ...extraWords]))
        const origChars: string[] = [...text];
        const len: number = origChars.length;
        const marks: any[] = Array(len).fill(false);

        allWords.forEach(word => {
            const nword: string = this.normalise(word);
            for (let i = 0; i < len; i++) {
                for (let l = 1;l <= Math.min(20, len - i); l++) {
                    const slice = origChars.slice(i, i + l).join('');
                    if(this.normalise(slice) === nword) {
                        for (let k = i; k < i + l; k++) marks[k] = true
                    }
                }
            }
        });

        let result: string = '';
        for (let i = 0; i < len; i++) {
            if(marks[i]) {
                if (censorChar && (i === 0 || !marks[i - 1])) {
                    result += censorChar.repeat(1);
                }
            } else {
                result += origChars[i]
            }
        }
        return result;
    }
}