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Abstract _.pick and _.omit via pick wrapper #1639

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Abstract _.pick and _.omit via pick wrapper #1639

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Abstract _.pick and _.omit via pick wrapper 
Use a pickerCreator function to create omit and pick
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@gyeates
gyeates committed May 20, 2014
commit e72b42692c3c8ecc41baa04cc383fbaac63eb995
50 changes: 23 additions & 27 deletions underscore.js
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Original file line number Diff line number Diff line change
Expand Up @@ -888,37 +888,33 @@
return obj;
};

// Return a copy of the object only containing the whitelisted properties.
_.pick = function(obj, iterator, context) {
var result = {}, key;
if (_.isFunction(iterator)) {
for (key in obj) {
var value = obj[key];
if (iterator.call(context, value, key, obj)) result[key] = value;
}
} else {
var keys = concat.apply([], slice.call(arguments, 1));
for (var i = 0, length = keys.length; i < length; i++) {
key = keys[i];
if (key in obj) result[key] = obj[key];
// internal wrapper around a key picker
var createPicker = function(negateResult) {
return function(obj, iterator, context) {
var result = {},
state, key;
if (_.isFunction(iterator)) {
iterator = createCallback(iterator, context);
for (key in obj) {
state = iterator(obj[key], key, obj);
if (negateResult ? !state : state) result[key] = obj[key];
}
} else {
var keys = _.invert(concat.apply([], slice.call(arguments, 1)));
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Let me know if the old way is preferred

Old way:

keys = _.map(concat.apply([], slice.call(arguments, 1)), String);
iterator = function(value, key) { return !_.contains(keys, key); };

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http://jsperf.com/invert-vs-map which should be used for this case?

for (key in obj) {
state = key in keys;
if (negateResult ? !state : state) result[key] = obj[key];
}
}
}
return result;
return result;
};
};

// Return a copy of the object only containing the whitelisted properties.
_.pick = createPicker(false);

// Return a copy of the object without the blacklisted properties.
_.omit = function(obj, iterator, context) {
var keys;
if (_.isFunction(iterator)) {
iterator = _.negate(iterator);
} else {
keys = _.map(concat.apply([], slice.call(arguments, 1)), String);
iterator = function(value, key) {
return !_.contains(keys, key);
};
}
return _.pick(obj, iterator, context);
};
_.omit = createPicker(true);

// Fill in a given object with default properties.
_.defaults = function(obj) {
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