谁能指出我在ecma-262中定义使用括号作为回报的标准吗？

Question

// Create a component named MessageComponent
var MessageComponent = React.createClass({
  render: function() {
    return (
      <div>{this.props.message}</div>
    );
  }
});

NOTE Why do we need the parentheses around the return statement (line 3)? This is because of JavaScript's automatic semicolon insertion. Without the parentheses, JavaScript would ignore the following lines and return without a value. If the JSX starts on the same line as the return, then parentheses are not needed.

Taken from here .

Answer 1

There is no specific part of the spec that handles using parens for returns. Parenthesis is just one way to create an expression.

Answer 2

When a continue, break, return, or throw token is encountered and a LineTerminator is encountered before the next token, a semicolon is automatically inserted after the continue, break, return, or throw token.

http://www.ecma-international.org/ecma-262/5.1/

Looks like the parentheses here are just vanilla JS expressions wrapped in parentheses ie return (1 + 2), except multi-line:

function x() {
    return (
        1 + 2
    );
}

*Edited to not use the word closure.