lib/engine_underscore.js
function (partialString) {
    var edgeQuotesMatcher = /^["']|["']$/g;
    var partialIDWithQuotes = partialString.replace(this.findPartialsRE, '$1');
    var partialID = partialIDWithQuotes.replace(edgeQuotesMatcher, '');

    return partialID;
  }
function (partialString) {
    var edgeQuotesMatcher = /^["']|["']$/g;
    var partialIDWithQuotes = partialString.replace(this.findPartialsRE, '$1');
    var partialID = partialIDWithQuotes.replace(edgeQuotesMatcher, '');

    return partialID;
  }
function ( partialString ) { var edgeQuotesMatcher = / ^["']|["']$ / g ; var partialIDWithQuotes = partialString . replace ( this . findPartialsRE , '$1' ) ; var partialID = partialIDWithQuotes . replace ( edgeQuotesMatcher , '' ) ; return partialID ; }
given a pattern, and a partial string, tease out the "pattern key" and return it.
given a pattern and a partial string tease out the pattern key and return it .