Created
June 5, 2011 20:30
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Real, deep copied objects.
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| function clone( obj ) { | |
| var val, length, i, | |
| temp = []; | |
| if ( Array.isArray(obj) ) { | |
| for ( i = 0, length = obj.length; i < length; i++ ) { | |
| // Store reference to this array item's value | |
| val = obj[ i ]; | |
| // If array item is an object (including arrays), derive new value by cloning | |
| if ( typeof val === "object" ) { | |
| val = clone( val ); | |
| } | |
| temp[ i ] = val; | |
| } | |
| return temp; | |
| } | |
| // Create a new object whose prototype is a new, empty object, | |
| // Using the second properties object argument to copy the source properties | |
| return Object.create({}, (function( src ) { | |
| // Initialize a cache for non-inherited properties | |
| var props = {}; | |
| Object.getOwnPropertyNames( src ).forEach(function( name ) { | |
| // Store short reference to property descriptor | |
| var descriptor = Object.getOwnPropertyDescriptor( src, name ); | |
| // Recurse on properties whose value is an object or array | |
| if ( typeof src[ name ] === "object" ) { | |
| descriptor.value = clone( src[ name ] ); | |
| } | |
| props[ name ] = descriptor; | |
| }); | |
| return props; | |
| }( obj ))); | |
| } |
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| var orig = { | |
| foo: "bar", | |
| inner: { | |
| prop: false, | |
| array: [ 1, 2, 3, 4, 5 ] | |
| } | |
| }, | |
| cloned = clone( orig ); | |
| console.log( | |
| ( cloned.hasOwnProperty("foo") && "PASS" ) || "FAIL", cloned.foo | |
| ); | |
| console.log( | |
| ( cloned.hasOwnProperty("inner") && "PASS" ) || "FAIL", cloned.inner | |
| ); | |
| console.log( | |
| ( cloned.inner.hasOwnProperty("prop") && "PASS" ) || "FAIL", cloned.inner.prop | |
| ); | |
| console.log( | |
| ( cloned.inner.hasOwnProperty("array") && "PASS" ) || "FAIL", cloned.inner.array | |
| ); | |
| // Change a value of the original `inner.array` | |
| cloned.inner.array[0] = "a"; | |
| console.log( | |
| ( orig.inner.array[0] !== cloned.inner.array[0] && "PASS" ) || "FAIL", | |
| orig.inner.array[0], | |
| cloned.inner.array[0] | |
| ); | |
| cloned.foo = "qux"; | |
| console.log( | |
| ( orig.foo !== cloned.foo && "PASS" ) || "FAIL", orig.foo, cloned.foo | |
| ); |
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Demo & tests: http://jsfiddle.net/rwaldron/4SEGz/
Results in console