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recursaprop: Eliminates the need to do data && data.prop && data.prop.subprop testing when accessing properties of objects. Given a dot-notated property (foo.bar.baz) of an object, returns the property or undefined if it or any step in the path does not exist.
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| // Eliminates the need to do data && data.prop && data.prop.subprop testing | |
| // when accessing properties of objects. | |
| function recursaprop( | |
| s, // property string in dot notation e.g. foo.bar.baz | |
| d, // data object | |
| p, // placeholder for prop list | |
| l, // placeholder for prop list length | |
| i, // placeholder of iteration index | |
| r, // placeholder for result | |
| u // placeholder for undefined | |
| ) { | |
| r = d; | |
| p = s.split('.'); // populate prop list from property string | |
| l = p.length; // get length | |
| for (i=0; i<l; i++) { | |
| r = r[p[i]]; // set result to be result's child property from prop list | |
| if (r === u) return r; // if we didn't find anything, return early | |
| } | |
| return r; | |
| } |
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| function recursaprop(a,b,c,d,e,f,g){for(f=b,c=a.split("."),d=c.length,e=0;d>e;e++)if(f=f[c[e]],f===g)return f;return f} |
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| DO WHAT THE HECK YOU WANT TO PUBLIC LICENSE | |
| Version 1, December 2013 | |
| Copyright (C) 2013 Aaron McCall <https://github.com/aaronmccall> | |
| Everyone is permitted to copy and distribute verbatim or modified | |
| copies of this license document, and changing it is allowed as long | |
| as the name is changed. | |
| DO WHAT THE HECK YOU WANT TO PUBLIC LICENSE | |
| TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION | |
| 0. You just DO WHAT THE HECK YOU WANT TO. |
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| { | |
| "name": "recursaprop", | |
| "description": "Given a dot-notated property (foo.bar.baz) of an object, returns the property or undefined if it or any step in the path does not exist.", | |
| "keywords": [ | |
| "object", | |
| "properties", | |
| "recursive" | |
| ] | |
| } |
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| <!DOCTYPE html> | |
| <title>Foo</title> | |
| <div>Expected value: <b>biz</b></div> | |
| <div>Actual value: <b id="ret"></b></div> | |
| <script> | |
| // write a small example that shows off the API for your example | |
| // and tests it in one fell swoop. | |
| function recursaprop(a,b,c,d,e,f,g){for(f=b,c=a.split("."),d=c.length,e=0;d>e;e++)if(f=f[c[e]],f===g)return f;return f} | |
| var obj = { | |
| foo: { | |
| bar: { | |
| baz: 'biz' | |
| } | |
| } | |
| }; | |
| document.getElementById( "ret" ).innerHTML = recursaprop('foo.bar.baz', obj); | |
| </script> |
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Smaller variant (70 bytes) using regexp: