| "use strict"; |
| Object.defineProperty(exports, "__esModule", { value: true }); |
| const boundaries_1 = require("./boundaries"); |
| // BreakTypes |
| // @type {BreakType} |
| const NotBreak = 0; |
| const BreakStart = 1; |
| const Break = 2; |
| const BreakLastRegional = 3; |
| const BreakPenultimateRegional = 4; |
| class GraphemerHelper { |
| /** |
| * Check if the the character at the position {pos} of the string is surrogate |
| * @param str {string} |
| * @param pos {number} |
| * @returns {boolean} |
| */ |
| static isSurrogate(str, pos) { |
| return (0xd800 <= str.charCodeAt(pos) && |
| str.charCodeAt(pos) <= 0xdbff && |
| 0xdc00 <= str.charCodeAt(pos + 1) && |
| str.charCodeAt(pos + 1) <= 0xdfff); |
| } |
| /** |
| * The String.prototype.codePointAt polyfill |
| * Private function, gets a Unicode code point from a JavaScript UTF-16 string |
| * handling surrogate pairs appropriately |
| * @param str {string} |
| * @param idx {number} |
| * @returns {number} |
| */ |
| static codePointAt(str, idx) { |
| if (idx === undefined) { |
| idx = 0; |
| } |
| const code = str.charCodeAt(idx); |
| // if a high surrogate |
| if (0xd800 <= code && code <= 0xdbff && idx < str.length - 1) { |
| const hi = code; |
| const low = str.charCodeAt(idx + 1); |
| if (0xdc00 <= low && low <= 0xdfff) { |
| return (hi - 0xd800) * 0x400 + (low - 0xdc00) + 0x10000; |
| } |
| return hi; |
| } |
| // if a low surrogate |
| if (0xdc00 <= code && code <= 0xdfff && idx >= 1) { |
| const hi = str.charCodeAt(idx - 1); |
| const low = code; |
| if (0xd800 <= hi && hi <= 0xdbff) { |
| return (hi - 0xd800) * 0x400 + (low - 0xdc00) + 0x10000; |
| } |
| return low; |
| } |
| // just return the char if an unmatched surrogate half or a |
| // single-char codepoint |
| return code; |
| } |
| // |
| /** |
| * Private function, returns whether a break is allowed between the two given grapheme breaking classes |
| * Implemented the UAX #29 3.1.1 Grapheme Cluster Boundary Rules on extended grapheme clusters |
| * @param start {number} |
| * @param mid {Array<number>} |
| * @param end {number} |
| * @param startEmoji {number} |
| * @param midEmoji {Array<number>} |
| * @param endEmoji {number} |
| * @returns {number} |
| */ |
| static shouldBreak(start, mid, end, startEmoji, midEmoji, endEmoji) { |
| const all = [start].concat(mid).concat([end]); |
| const allEmoji = [startEmoji].concat(midEmoji).concat([endEmoji]); |
| const previous = all[all.length - 2]; |
| const next = end; |
| const nextEmoji = endEmoji; |
| // Lookahead terminator for: |
| // GB12. ^ (RI RI)* RI ? RI |
| // GB13. [^RI] (RI RI)* RI ? RI |
| const rIIndex = all.lastIndexOf(boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR); |
| if (rIIndex > 0 && |
| all.slice(1, rIIndex).every(function (c) { |
| return c === boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR; |
| }) && |
| [boundaries_1.CLUSTER_BREAK.PREPEND, boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR].indexOf(previous) === -1) { |
| if (all.filter(function (c) { |
| return c === boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR; |
| }).length % |
| 2 === |
| 1) { |
| return BreakLastRegional; |
| } |
| else { |
| return BreakPenultimateRegional; |
| } |
| } |
| // GB3. CR × LF |
| if (previous === boundaries_1.CLUSTER_BREAK.CR && next === boundaries_1.CLUSTER_BREAK.LF) { |
| return NotBreak; |
| } |
| // GB4. (Control|CR|LF) ÷ |
| else if (previous === boundaries_1.CLUSTER_BREAK.CONTROL || |
| previous === boundaries_1.CLUSTER_BREAK.CR || |
| previous === boundaries_1.CLUSTER_BREAK.LF) { |
| return BreakStart; |
| } |
| // GB5. ÷ (Control|CR|LF) |
| else if (next === boundaries_1.CLUSTER_BREAK.CONTROL || |
| next === boundaries_1.CLUSTER_BREAK.CR || |
| next === boundaries_1.CLUSTER_BREAK.LF) { |
| return BreakStart; |
| } |
| // GB6. L × (L|V|LV|LVT) |
| else if (previous === boundaries_1.CLUSTER_BREAK.L && |
| (next === boundaries_1.CLUSTER_BREAK.L || |
| next === boundaries_1.CLUSTER_BREAK.V || |
| next === boundaries_1.CLUSTER_BREAK.LV || |
| next === boundaries_1.CLUSTER_BREAK.LVT)) { |
| return NotBreak; |
| } |
| // GB7. (LV|V) × (V|T) |
| else if ((previous === boundaries_1.CLUSTER_BREAK.LV || previous === boundaries_1.CLUSTER_BREAK.V) && |
| (next === boundaries_1.CLUSTER_BREAK.V || next === boundaries_1.CLUSTER_BREAK.T)) { |
| return NotBreak; |
| } |
| // GB8. (LVT|T) × (T) |
| else if ((previous === boundaries_1.CLUSTER_BREAK.LVT || previous === boundaries_1.CLUSTER_BREAK.T) && |
| next === boundaries_1.CLUSTER_BREAK.T) { |
| return NotBreak; |
| } |
| // GB9. × (Extend|ZWJ) |
| else if (next === boundaries_1.CLUSTER_BREAK.EXTEND || next === boundaries_1.CLUSTER_BREAK.ZWJ) { |
| return NotBreak; |
| } |
| // GB9a. × SpacingMark |
| else if (next === boundaries_1.CLUSTER_BREAK.SPACINGMARK) { |
| return NotBreak; |
| } |
| // GB9b. Prepend × |
| else if (previous === boundaries_1.CLUSTER_BREAK.PREPEND) { |
| return NotBreak; |
| } |
| // GB11. \p{Extended_Pictographic} Extend* ZWJ × \p{Extended_Pictographic} |
| const previousNonExtendIndex = allEmoji |
| .slice(0, -1) |
| .lastIndexOf(boundaries_1.EXTENDED_PICTOGRAPHIC); |
| if (previousNonExtendIndex !== -1 && |
| allEmoji[previousNonExtendIndex] === boundaries_1.EXTENDED_PICTOGRAPHIC && |
| all.slice(previousNonExtendIndex + 1, -2).every(function (c) { |
| return c === boundaries_1.CLUSTER_BREAK.EXTEND; |
| }) && |
| previous === boundaries_1.CLUSTER_BREAK.ZWJ && |
| nextEmoji === boundaries_1.EXTENDED_PICTOGRAPHIC) { |
| return NotBreak; |
| } |
| // GB12. ^ (RI RI)* RI × RI |
| // GB13. [^RI] (RI RI)* RI × RI |
| if (mid.indexOf(boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR) !== -1) { |
| return Break; |
| } |
| if (previous === boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR && |
| next === boundaries_1.CLUSTER_BREAK.REGIONAL_INDICATOR) { |
| return NotBreak; |
| } |
| // GB999. Any ? Any |
| return BreakStart; |
| } |
| } |
| exports.default = GraphemerHelper; |
