JavaScript: Keywords array to Regular Expression

gistfile1.js

/**
     * Takes an array of keywords and turn it into a regular expression 
     * that can be tested to see if a word matches any in the array
     * irregardless of white space and case
     * @param  {Array} arrKeywords Array of Keywords
     * @return {RegExp}             Regular Expression
     */
    function createExpression (arrKeywords) {
        var innerExpression = '';
        [].forEach.call(arrKeywords, function (k, index) {
            innerExpression += k.replace(' ', '\\s?')
            // Add pipe so other keywords are appended to regex
            if(index !== arrKeywords.length -1)
                innerExpression += "|";
        });
        var regEx = new RegExp('\\b(' + innerExpression + ')', 'i');
        return regEx;

        //  FINAL RESULT
        //  /\b(Price|Master\s?Price|Regular\s?Price)/i
    }