node_modules

1 files changed, 214 insertions, 0 deletions

diff --git a/node_modules/fbjs/lib/UnicodeUtils.js b/node_modules/fbjs/lib/UnicodeUtils.js
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+/**
+ * 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
+ */
+
+/**
+ * Unicode-enabled replacesments for basic String functions.
+ *
+ * All the functions in this module assume that the input string is a valid
+ * UTF-16 encoding of a Unicode sequence. If it's not the case, the behavior
+ * will be undefined.
+ *
+ * WARNING: Since this module is typechecks-enforced, you may find new bugs
+ * when replacing normal String functions with ones provided here.
+ */
+
+'use strict';
+
+var invariant = require('./invariant');
+
+// These two ranges are consecutive so anything in [HIGH_START, LOW_END] is a
+// surrogate code unit.
+var SURROGATE_HIGH_START = 0xD800;
+var SURROGATE_HIGH_END = 0xDBFF;
+var SURROGATE_LOW_START = 0xDC00;
+var SURROGATE_LOW_END = 0xDFFF;
+var SURROGATE_UNITS_REGEX = /[\uD800-\uDFFF]/;
+
+/**
+ * @param {number} codeUnit   A Unicode code-unit, in range [0, 0x10FFFF]
+ * @return {boolean}          Whether code-unit is in a surrogate (hi/low) range
+ */
+function isCodeUnitInSurrogateRange(codeUnit) {
+  return SURROGATE_HIGH_START <= codeUnit && codeUnit <= SURROGATE_LOW_END;
+}
+
+/**
+ * Returns whether the two characters starting at `index` form a surrogate pair.
+ * For example, given the string s = "\uD83D\uDE0A", (s, 0) returns true and
+ * (s, 1) returns false.
+ *
+ * @param {string} str
+ * @param {number} index
+ * @return {boolean}
+ */
+function isSurrogatePair(str, index) {
+  !(0 <= index && index < str.length) ? process.env.NODE_ENV !== 'production' ? invariant(false, 'isSurrogatePair: Invalid index %s for string length %s.', index, str.length) : invariant(false) : void 0;
+  if (index + 1 === str.length) {
+    return false;
+  }
+  var first = str.charCodeAt(index);
+  var second = str.charCodeAt(index + 1);
+  return SURROGATE_HIGH_START <= first && first <= SURROGATE_HIGH_END && SURROGATE_LOW_START <= second && second <= SURROGATE_LOW_END;
+}
+
+/**
+ * @param {string} str  Non-empty string
+ * @return {boolean}    True if the input includes any surrogate code units
+ */
+function hasSurrogateUnit(str) {
+  return SURROGATE_UNITS_REGEX.test(str);
+}
+
+/**
+ * Return the length of the original Unicode character at given position in the
+ * String by looking into the UTF-16 code unit; that is equal to 1 for any
+ * non-surrogate characters in BMP ([U+0000..U+D7FF] and [U+E000, U+FFFF]); and
+ * returns 2 for the hi/low surrogates ([U+D800..U+DFFF]), which are in fact
+ * representing non-BMP characters ([U+10000..U+10FFFF]).
+ *
+ * Examples:
+ * - '\u0020' => 1
+ * - '\u3020' => 1
+ * - '\uD835' => 2
+ * - '\uD835\uDDEF' => 2
+ * - '\uDDEF' => 2
+ *
+ * @param {string} str  Non-empty string
+ * @param {number} pos  Position in the string to look for one code unit
+ * @return {number}      Number 1 or 2
+ */
+function getUTF16Length(str, pos) {
+  return 1 + isCodeUnitInSurrogateRange(str.charCodeAt(pos));
+}
+
+/**
+ * Fully Unicode-enabled replacement for String#length
+ *
+ * @param {string} str  Valid Unicode string
+ * @return {number}     The number of Unicode characters in the string
+ */
+function strlen(str) {
+  // Call the native functions if there's no surrogate char
+  if (!hasSurrogateUnit(str)) {
+    return str.length;
+  }
+
+  var len = 0;
+  for (var pos = 0; pos < str.length; pos += getUTF16Length(str, pos)) {
+    len++;
+  }
+  return len;
+}
+
+/**
+ * Fully Unicode-enabled replacement for String#substr()
+ *
+ * @param {string} str      Valid Unicode string
+ * @param {number} start    Location in Unicode sequence to begin extracting
+ * @param {?number} length  The number of Unicode characters to extract
+ *                          (default: to the end of the string)
+ * @return {string}         Extracted sub-string
+ */
+function substr(str, start, length) {
+  start = start || 0;
+  length = length === undefined ? Infinity : length || 0;
+
+  // Call the native functions if there's no surrogate char
+  if (!hasSurrogateUnit(str)) {
+    return str.substr(start, length);
+  }
+
+  // Obvious cases
+  var size = str.length;
+  if (size <= 0 || start > size || length <= 0) {
+    return '';
+  }
+
+  // Find the actual starting position
+  var posA = 0;
+  if (start > 0) {
+    for (; start > 0 && posA < size; start--) {
+      posA += getUTF16Length(str, posA);
+    }
+    if (posA >= size) {
+      return '';
+    }
+  } else if (start < 0) {
+    for (posA = size; start < 0 && 0 < posA; start++) {
+      posA -= getUTF16Length(str, posA - 1);
+    }
+    if (posA < 0) {
+      posA = 0;
+    }
+  }
+
+  // Find the actual ending position
+  var posB = size;
+  if (length < size) {
+    for (posB = posA; length > 0 && posB < size; length--) {
+      posB += getUTF16Length(str, posB);
+    }
+  }
+
+  return str.substring(posA, posB);
+}
+
+/**
+ * Fully Unicode-enabled replacement for String#substring()
+ *
+ * @param {string} str    Valid Unicode string
+ * @param {number} start  Location in Unicode sequence to begin extracting
+ * @param {?number} end   Location in Unicode sequence to end extracting
+ *                        (default: end of the string)
+ * @return {string}       Extracted sub-string
+ */
+function substring(str, start, end) {
+  start = start || 0;
+  end = end === undefined ? Infinity : end || 0;
+
+  if (start < 0) {
+    start = 0;
+  }
+  if (end < 0) {
+    end = 0;
+  }
+
+  var length = Math.abs(end - start);
+  start = start < end ? start : end;
+  return substr(str, start, length);
+}
+
+/**
+ * Get a list of Unicode code-points from a String
+ *
+ * @param {string} str        Valid Unicode string
+ * @return {array<number>}    A list of code-points in [0..0x10FFFF]
+ */
+function getCodePoints(str) {
+  var codePoints = [];
+  for (var pos = 0; pos < str.length; pos += getUTF16Length(str, pos)) {
+    codePoints.push(str.codePointAt(pos));
+  }
+  return codePoints;
+}
+
+var UnicodeUtils = {
+  getCodePoints: getCodePoints,
+  getUTF16Length: getUTF16Length,
+  hasSurrogateUnit: hasSurrogateUnit,
+  isCodeUnitInSurrogateRange: isCodeUnitInSurrogateRange,
+  isSurrogatePair: isSurrogatePair,
+  strlen: strlen,
+  substring: substring,
+  substr: substr
+};
+
+module.exports = UnicodeUtils;
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