Create regex from object keys

Question

How can I simplify the following better using Underscore? It feels like too much code for something very simple. It creates a regex from the object keys.

var obj = {
   'dog' : 1,
   'cat' : 1,
   'rat' : 1
};

var arr = [], regex;

_.each( obj, function( value, index ){
  arr.push( index );
});

regex = _.reduce( arr, function(){
  return new RegExp( arr.join('|'), 'i' );
});

// console.log( regex ) should output: 
/dog|cat|rat/i

thefourtheye · Accepted Answer · 2015-01-10 17:54:35Z

1

Simply use Object.keys and native Array.prototype.join like this

console.log(new RegExp(Object.keys(obj).join("|"), "i"));

With _, it will be _.keys

console.log(new RegExp(_.keys(obj).join("|"), "i"));

The result would be

/dog|cat|rat/i

answered Jan 10, 2015 at 17:54

thefourtheye

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1 Comment

cusejuice Over a year ago

Awesome, I landed on the first one, but +1 for included the Underscore version.

cusejuice · Accepted Answer · 2015-01-10 17:54:06Z

0

I quickly figured that you don't need to use underscore for this.

 var regex = new RegExp( Object.keys( obj ).join('|'), 'i' );

answered Jan 10, 2015 at 17:54

cusejuice

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