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Add assignValue and assignMergeValue helpers to make value assignments more consistent across methods.

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This commit is contained in:
John-David Dalton
2015-07-26 09:42:21 -07:00
parent ce569e4bc4
commit 731d5b6872
2 changed files with 92 additions and 68 deletions
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116
lodash.js
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@@ -1517,6 +1517,42 @@
return result;
}
/**
* Assigns `value` to `key` of `object` if the existing value is not equivalent
* using [`SameValueZero`](http://ecma-international.org/ecma-262/6.0/#sec-samevaluezero)
* for equality comparisons.
*
* @private
* @param {Object} object The object to augment.
* @param {string} key The key of the property to assign.
* @param {*} value The value to assign.
*/
function assignValue(object, key, value) {
var oldValue = object[key];
if ((value === value ? (value !== oldValue) : (oldValue === oldValue)) ||
(value === undefined && !(key in object))) {
object[key] = value;
}
}
/**
* This function is like `assignValue` except that it doesn't assign `undefined` values.
*
* @private
* @param {Object} object The object to augment.
* @param {string} key The key of the property to assign.
* @param {*} value The value to assign.
*/
function assignMergeValue(object, key, value) {
var oldValue = object[key];
if ((value !== undefined &&
(value === value ? (value !== oldValue) : (oldValue === oldValue))) ||
(typeof key == 'number' &&
value === undefined && !(key in object))) {
object[key] = value;
}
}
/**
* The base implementation of `_.assign` without support for multiple sources
* or `customizer` functions.
@@ -2235,12 +2271,9 @@
* @param {Function} [customizer] The function to customize merged values.
* @param {Array} [stackA=[]] Tracks traversed source objects.
* @param {Array} [stackB=[]] Associates values with source counterparts.
* @returns {Object} Returns `object`.
*/
function baseMerge(object, source, customizer, stackA, stackB) {
var isSrcArr = isArrayLike(source) && (isArray(source) || isTypedArray(source)),
props = isSrcArr ? undefined : keysIn(source);
var props = (isArray(source) || isTypedArray(source)) ? undefined : keysIn(source);
arrayEach(props || source, function(srcValue, key) {
if (props) {
key = srcValue;
@@ -2252,20 +2285,13 @@
baseMergeDeep(object, source, key, baseMerge, customizer, stackA, stackB);
}
else {
var value = object[key],
result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
isCommon = result === undefined;
if (isCommon) {
result = srcValue;
}
if ((result !== undefined || (isSrcArr && !(key in object))) &&
(isCommon || (result === result ? (result !== value) : (value === value)))) {
object[key] = result;
var newValue = customizer ? customizer(object[key], srcValue, (key + ''), object, source) : undefined;
if (newValue === undefined) {
newValue = srcValue;
}
assignMergeValue(object, key, newValue);
}
});
return object;
}
/**
@@ -2281,33 +2307,32 @@
* @param {Function} [customizer] The function to customize assigned values.
* @param {Array} [stackA=[]] Tracks traversed source objects.
* @param {Array} [stackB=[]] Associates values with source counterparts.
* @returns {boolean} Returns `true` if the objects are equivalent, else `false`.
*/
function baseMergeDeep(object, source, key, mergeFunc, customizer, stackA, stackB) {
var length = stackA.length,
oldValue = object[key],
srcValue = source[key];
while (length--) {
if (stackA[length] == srcValue) {
object[key] = stackB[length];
assignMergeValue(object, key, stackB[length]);
return;
}
}
var value = object[key],
result = customizer ? customizer(value, srcValue, key, object, source) : undefined,
isCommon = result === undefined;
var newValue = customizer ? customizer(oldValue, srcValue, (key + ''), object, source) : undefined,
isCommon = newValue === undefined;
if (isCommon) {
result = srcValue;
if (isArrayLike(srcValue) && (isArray(srcValue) || isTypedArray(srcValue))) {
result = isArray(value)
? value
: (isArrayLike(value) ? copyArray(value) : []);
newValue = srcValue;
if (isArray(srcValue) || isTypedArray(srcValue)) {
newValue = isArray(oldValue)
? oldValue
: (isArrayLike(oldValue) ? copyArray(oldValue) : []);
}
else if (isPlainObject(srcValue) || isArguments(srcValue)) {
result = isArguments(value)
? toPlainObject(value)
: (isPlainObject(value) ? value : {});
newValue = isArguments(oldValue)
? toPlainObject(oldValue)
: (isPlainObject(oldValue) ? oldValue : {});
}
else {
isCommon = false;
@@ -2316,14 +2341,13 @@
// Add the source value to the stack of traversed objects and associate
// it with its merged value.
stackA.push(srcValue);
stackB.push(result);
stackB.push(newValue);
if (isCommon) {
// Recursively merge objects and arrays (susceptible to call stack limits).
object[key] = mergeFunc(result, srcValue, customizer, stackA, stackB);
} else if (result === result ? (result !== value) : (value === value)) {
object[key] = result;
mergeFunc(newValue, srcValue, customizer, stackA, stackB);
}
assignMergeValue(object, key, newValue);
}
/**
@@ -2471,9 +2495,10 @@
*
* @private
* @param {Object} object The object to query.
* @param {Array|string} path The path of the property to get.
* @param {Function} [customizer] The function to customize cloning.
* @returns {*} Returns the resolved value.
* @param {Array|string} path The path of the property to set.
* @param {*} value The value to set.
* @param {Function} [customizer] The function to customize path creation.
* @returns {Object} Returns `object`.
*/
function baseSet(object, path, value, customizer) {
path = isKey(path, object) ? [path + ''] : toPath(path);
@@ -2490,13 +2515,13 @@
nested[key] = value;
}
else {
var other = nested[key],
result = customizer ? customizer(other, key, nested) : undefined;
var oldValue = nested[key],
newValue = customizer ? customizer(oldValue, key, nested) : undefined;
if (result === undefined) {
result = other == null ? (isIndex(path[index + 1]) ? [] : {}) : other;
if (newValue === undefined) {
newValue = oldValue == null ? (isIndex(path[index + 1]) ? [] : {}) : oldValue;
}
nested[key] = result;
assignValue(nested, key, newValue);
}
}
nested = nested[key];
@@ -2925,7 +2950,7 @@
while (++index < length) {
var key = props[index];
object[key] = source[key];
assignValue(object, key, source[key], object[key]);
}
return object;
}
@@ -2949,14 +2974,9 @@
while (++index < length) {
var key = props[index],
value = object[key],
result = customizer ? customizer(value, source[key], key, object, source) : source[key];
newValue = customizer ? customizer(object[key], source[key], key, object, source) : source[key];
if (!customizer ||
(result === result ? (result !== value) : (value === value)) ||
(value === undefined && !(key in object))) {
object[key] = result;
}
assignValue(object, key, newValue);
}
return object;
}

44
test/test.js
View File

@@ -5107,6 +5107,30 @@
});
});
_.each(['assign', 'assignWith', 'defaults', 'extend', 'extendWith', 'merge', 'mergeWith'], function(methodName) {
var func = _[methodName];
test('`_.' + methodName + '` should not assign values that are the same as their destinations', 4, function() {
_.each(['a', ['a'], { 'a': 1 }, NaN], function(value) {
if (defineProperty) {
var object = {},
pass = true;
defineProperty(object, 'a', {
'get': _.constant(value),
'set': function() { pass = false; }
});
func(object, { 'a': value }, _.identity);
ok(pass, value);
}
else {
skipTest();
}
});
});
});
_.each(['assignWith', 'extendWith', 'mergeWith'], function(methodName) {
var func = _[methodName],
isMergeWith = methodName == 'mergeWith';
@@ -5160,26 +5184,6 @@
actual = func({ 'a': 1 }, callback, { 'c': 3 });
deepEqual(actual, { 'a': 1, 'b': 2, 'c': 3 });
});
test('`_.' + methodName + '` should not assign the `customizer` result if it is the same as the destination value', 4, function() {
_.each(['a', ['a'], { 'a': 1 }, NaN], function(value) {
if (defineProperty) {
var object = {},
pass = true;
defineProperty(object, 'a', {
'get': _.constant(value),
'set': function() { pass = false; }
});
func(object, { 'a': value }, _.identity);
ok(pass);
}
else {
skipTest();
}
});
});
});
/*--------------------------------------------------------------------------*/