chiffon.js
function(allowIn) {
      var node = this.startNode(_SequenceExpression);
      var expr = this.parseAssignmentExpression(allowIn);
      if (this.value !== ',') {
        return expr;
      }

      var exprs = [expr];

      do {
        this.next();
        exprs[exprs.length] = this.parseAssignmentExpression(allowIn);
      } while (this.value === ',');

      node.expressions = exprs;
      return this.finishNode(node);
    }
function(allowIn) {
      var node = this.startNode(_SequenceExpression);
      var expr = this.parseAssignmentExpression(allowIn);
      if (this.value !== ',') {
        return expr;
      }

      var exprs = [expr];

      do {
        this.next();
        exprs[exprs.length] = this.parseAssignmentExpression(allowIn);
      } while (this.value === ',');

      node.expressions = exprs;
      return this.finishNode(node);
    }
function ( allowIn ) { var node = this . startNode ( _SequenceExpression ) ; var expr = this . parseAssignmentExpression ( allowIn ) ; if ( this . value !== ',' ) { return expr ; } var exprs = [ expr ] ; do { this . next ( ) ; exprs [ exprs . length ] = this . parseAssignmentExpression ( allowIn ) ; } while ( this . value === ',' ) ; node . expressions = exprs ; return this . finishNode ( node ) ; }
ECMA-262 A.2 Expressions
ECMA - 262 A . 2 Expressions