basant307/AI_Governance_Project

1"use strict";2Object.defineProperty(exports, "__esModule", { value: true });3const boundaries_1 = require("./boundaries");4// BreakTypes5// @type {BreakType}6const NotBreak = 0;7const BreakStart = 1;8const Break = 2;9const BreakLastRegional = 3;10const BreakPenultimateRegional = 4;11class GraphemerHelper {12    /**13     * Check if the the character at the position {pos} of the string is surrogate14     * @param str {string}15     * @param pos {number}16     * @returns {boolean}17     */18    static isSurrogate(str, pos) {19        return (0xd800 <= str.charCodeAt(pos) &&20            str.charCodeAt(pos) <= 0xdbff &&21            0xdc00 <= str.charCodeAt(pos + 1) &&22            str.charCodeAt(pos + 1) <= 0xdfff);23    }24    /**25     * The String.prototype.codePointAt polyfill26     * Private function, gets a Unicode code point from a JavaScript UTF-16 string27     * handling surrogate pairs appropriately28     * @param str {string}29     * @param idx {number}30     * @returns {number}31     */32    static codePointAt(str, idx) {33        if (idx === undefined) {34            idx = 0;35        }36        const code = str.charCodeAt(idx);37        // if a high surrogate38        if (0xd800 <= code && code <= 0xdbff && idx < str.length - 1) {39            const hi = code;40            const low = str.charCodeAt(idx + 1);41            if (0xdc00 <= low && low <= 0xdfff) {42                return (hi - 0xd800) * 0x400 + (low - 0xdc00) + 0x10000;43            }44            return hi;45        }46        // if a low surrogate47        if (0xdc00 <= code && code <= 0xdfff && idx >= 1) {48            const hi = str.charCodeAt(idx - 1);49            const low = code;50            if (0xd800 <= hi && hi <= 0xdbff) {51                return (hi - 0xd800) * 0x400 + (low - 0xdc00) + 0x10000;52            }53            return low;54        }55        // just return the char if an unmatched surrogate half or a56        // single-char codepoint57        return code;58    }59    //60    /**61     * Private function, returns whether a break is allowed between the two given grapheme breaking classes62     * Implemented the UAX #29 3.1.1 Grapheme Cluster Boundary Rules on extended grapheme clusters63     * @param start {number}64     * @param mid {Array<number>}65     * @param end {number}66     * @param startEmoji {number}67     * @param midEmoji {Array<number>}68     * @param endEmoji {number}69     * @returns {number}70     */71    static shouldBreak(start, mid, end, startEmoji, midEmoji, endEmoji) {72        const all = [start].concat(mid).concat([end]);73        const allEmoji = [startEmoji].concat(midEmoji).concat([endEmoji]);74        const previous = all[all.length - 2];75        const next = end;76        const nextEmoji = endEmoji;77        // Lookahead terminator for:78        // GB12. ^ (RI RI)* RI ? RI79        // GB13. [^RI] (RI RI)* RI ? RI80        const rIIndex = all.lastIndexOf(boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR);81        if (rIIndex > 0 &&82            all.slice(1, rIIndex).every(function (c) {83                return c === boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR;84            }) &&85            [boundaries_1.CLUSTER_BREAK.PREPEND, boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR].indexOf(previous) === -1) {86            if (all.filter(function (c) {87                return c === boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR;88            }).length %89                2 ===90                1) {91                return BreakLastRegional;92            }93            else {94                return BreakPenultimateRegional;95            }96        }97        // GB3. CR × LF98        if (previous === boundaries_1.CLUSTER_BREAK.CR && next === boundaries_1.CLUSTER_BREAK.LF) {99            return NotBreak;100        }101        // GB4. (Control|CR|LF) ÷102        else if (previous === boundaries_1.CLUSTER_BREAK.CONTROL ||103            previous === boundaries_1.CLUSTER_BREAK.CR ||104            previous === boundaries_1.CLUSTER_BREAK.LF) {105            return BreakStart;106        }107        // GB5. ÷ (Control|CR|LF)108        else if (next === boundaries_1.CLUSTER_BREAK.CONTROL ||109            next === boundaries_1.CLUSTER_BREAK.CR ||110            next === boundaries_1.CLUSTER_BREAK.LF) {111            return BreakStart;112        }113        // GB6. L × (L|V|LV|LVT)114        else if (previous === boundaries_1.CLUSTER_BREAK.L &&115            (next === boundaries_1.CLUSTER_BREAK.L ||116                next === boundaries_1.CLUSTER_BREAK.V ||117                next === boundaries_1.CLUSTER_BREAK.LV ||118                next === boundaries_1.CLUSTER_BREAK.LVT)) {119            return NotBreak;120        }121        // GB7. (LV|V) × (V|T)122        else if ((previous === boundaries_1.CLUSTER_BREAK.LV || previous === boundaries_1.CLUSTER_BREAK.V) &&123            (next === boundaries_1.CLUSTER_BREAK.V || next === boundaries_1.CLUSTER_BREAK.T)) {124            return NotBreak;125        }126        // GB8. (LVT|T) × (T)127        else if ((previous === boundaries_1.CLUSTER_BREAK.LVT || previous === boundaries_1.CLUSTER_BREAK.T) &&128            next === boundaries_1.CLUSTER_BREAK.T) {129            return NotBreak;130        }131        // GB9. × (Extend|ZWJ)132        else if (next === boundaries_1.CLUSTER_BREAK.EXTEND || next === boundaries_1.CLUSTER_BREAK.ZWJ) {133            return NotBreak;134        }135        // GB9a. × SpacingMark136        else if (next === boundaries_1.CLUSTER_BREAK.SPACINGMARK) {137            return NotBreak;138        }139        // GB9b. Prepend ×140        else if (previous === boundaries_1.CLUSTER_BREAK.PREPEND) {141            return NotBreak;142        }143        // GB11. \p{Extended_Pictographic} Extend* ZWJ × \p{Extended_Pictographic}144        const previousNonExtendIndex = allEmoji145            .slice(0, -1)146            .lastIndexOf(boundaries_1.EXTENDED_PICTOGRAPHIC);147        if (previousNonExtendIndex !== -1 &&148            allEmoji[previousNonExtendIndex] === boundaries_1.EXTENDED_PICTOGRAPHIC &&149            all.slice(previousNonExtendIndex + 1, -2).every(function (c) {150                return c === boundaries_1.CLUSTER_BREAK.EXTEND;151            }) &&152            previous === boundaries_1.CLUSTER_BREAK.ZWJ &&153            nextEmoji === boundaries_1.EXTENDED_PICTOGRAPHIC) {154            return NotBreak;155        }156        // GB12. ^ (RI RI)* RI × RI157        // GB13. [^RI] (RI RI)* RI × RI158        if (mid.indexOf(boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR) !== -1) {159            return Break;160        }161        if (previous === boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR &&162            next === boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR) {163            return NotBreak;164        }165        // GB999. Any ? Any166        return BreakStart;167    }168}169exports.default = GraphemerHelper;170