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Diffstat (limited to 'node_modules/fbjs/lib/UnicodeBidiService.js')
-rw-r--r-- | node_modules/fbjs/lib/UnicodeBidiService.js | 100 |
1 files changed, 100 insertions, 0 deletions
diff --git a/node_modules/fbjs/lib/UnicodeBidiService.js b/node_modules/fbjs/lib/UnicodeBidiService.js new file mode 100644 index 000000000..f7189d8ee --- /dev/null +++ b/node_modules/fbjs/lib/UnicodeBidiService.js @@ -0,0 +1,100 @@ +/** + * Copyright (c) 2013-present, Facebook, Inc. + * All rights reserved. + * + * This source code is licensed under the BSD-style license found in the + * LICENSE file in the root directory of this source tree. An additional grant + * of patent rights can be found in the PATENTS file in the same directory. + * + * @typechecks + * + */ + +/** + * Stateful API for text direction detection + * + * This class can be used in applications where you need to detect the + * direction of a sequence of text blocks, where each direction shall be used + * as the fallback direction for the next one. + * + * NOTE: A default direction, if not provided, is set based on the global + * direction, as defined by `UnicodeBidiDirection`. + * + * == Example == + * ``` + * var UnicodeBidiService = require('UnicodeBidiService'); + * + * var bidiService = new UnicodeBidiService(); + * + * ... + * + * bidiService.reset(); + * for (var para in paragraphs) { + * var dir = bidiService.getDirection(para); + * ... + * } + * ``` + * + * Part of our implementation of Unicode Bidirectional Algorithm (UBA) + * Unicode Standard Annex #9 (UAX9) + * http://www.unicode.org/reports/tr9/ + */ + +'use strict'; + +function _classCallCheck(instance, Constructor) { if (!(instance instanceof Constructor)) { throw new TypeError("Cannot call a class as a function"); } } + +var UnicodeBidi = require('./UnicodeBidi'); +var UnicodeBidiDirection = require('./UnicodeBidiDirection'); + +var invariant = require('./invariant'); + +var UnicodeBidiService = function () { + + /** + * Stateful class for paragraph direction detection + * + * @param defaultDir Default direction of the service + */ + function UnicodeBidiService(defaultDir) { + _classCallCheck(this, UnicodeBidiService); + + if (!defaultDir) { + defaultDir = UnicodeBidiDirection.getGlobalDir(); + } else { + !UnicodeBidiDirection.isStrong(defaultDir) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'Default direction must be a strong direction (LTR or RTL)') : invariant(false) : void 0; + } + this._defaultDir = defaultDir; + this.reset(); + } + + /** + * Reset the internal state + * + * Instead of creating a new instance, you can just reset() your instance + * everytime you start a new loop. + */ + + + UnicodeBidiService.prototype.reset = function reset() { + this._lastDir = this._defaultDir; + }; + + /** + * Returns the direction of a block of text, and remembers it as the + * fall-back direction for the next paragraph. + * + * @param str A text block, e.g. paragraph, table cell, tag + * @return The resolved direction + */ + + + UnicodeBidiService.prototype.getDirection = function getDirection(str) { + this._lastDir = UnicodeBidi.getDirection(str, this._lastDir); + return this._lastDir; + }; + + return UnicodeBidiService; +}(); + +module.exports = UnicodeBidiService;
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