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node_modules/deep-equal/index.js 2.98 KB
aaac7fed   liuqimichale   add
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  var pSlice = Array.prototype.slice;
  var objectKeys = require('./lib/keys.js');
  var isArguments = require('./lib/is_arguments.js');
  
  var deepEqual = module.exports = function (actual, expected, opts) {
    if (!opts) opts = {};
    // 7.1. All identical values are equivalent, as determined by ===.
    if (actual === expected) {
      return true;
  
    } else if (actual instanceof Date && expected instanceof Date) {
      return actual.getTime() === expected.getTime();
  
    // 7.3. Other pairs that do not both pass typeof value == 'object',
    // equivalence is determined by ==.
    } else if (!actual || !expected || typeof actual != 'object' && typeof expected != 'object') {
      return opts.strict ? actual === expected : actual == expected;
  
    // 7.4. For all other Object pairs, including Array objects, equivalence is
    // determined by having the same number of owned properties (as verified
    // with Object.prototype.hasOwnProperty.call), the same set of keys
    // (although not necessarily the same order), equivalent values for every
    // corresponding key, and an identical 'prototype' property. Note: this
    // accounts for both named and indexed properties on Arrays.
    } else {
      return objEquiv(actual, expected, opts);
    }
  }
  
  function isUndefinedOrNull(value) {
    return value === null || value === undefined;
  }
  
  function isBuffer (x) {
    if (!x || typeof x !== 'object' || typeof x.length !== 'number') return false;
    if (typeof x.copy !== 'function' || typeof x.slice !== 'function') {
      return false;
    }
    if (x.length > 0 && typeof x[0] !== 'number') return false;
    return true;
  }
  
  function objEquiv(a, b, opts) {
    var i, key;
    if (isUndefinedOrNull(a) || isUndefinedOrNull(b))
      return false;
    // an identical 'prototype' property.
    if (a.prototype !== b.prototype) return false;
    //~~~I've managed to break Object.keys through screwy arguments passing.
    //   Converting to array solves the problem.
    if (isArguments(a)) {
      if (!isArguments(b)) {
        return false;
      }
      a = pSlice.call(a);
      b = pSlice.call(b);
      return deepEqual(a, b, opts);
    }
    if (isBuffer(a)) {
      if (!isBuffer(b)) {
        return false;
      }
      if (a.length !== b.length) return false;
      for (i = 0; i < a.length; i++) {
        if (a[i] !== b[i]) return false;
      }
      return true;
    }
    try {
      var ka = objectKeys(a),
          kb = objectKeys(b);
    } catch (e) {//happens when one is a string literal and the other isn't
      return false;
    }
    // having the same number of owned properties (keys incorporates
    // hasOwnProperty)
    if (ka.length != kb.length)
      return false;
    //the same set of keys (although not necessarily the same order),
    ka.sort();
    kb.sort();
    //~~~cheap key test
    for (i = ka.length - 1; i >= 0; i--) {
      if (ka[i] != kb[i])
        return false;
    }
    //equivalent values for every corresponding key, and
    //~~~possibly expensive deep test
    for (i = ka.length - 1; i >= 0; i--) {
      key = ka[i];
      if (!deepEqual(a[key], b[key], opts)) return false;
    }
    return typeof a === typeof b;
  }