Reproduce issue #426

[lucivpav]

Reproduces #426

[Meir017]

@lucivpav I just ran into this issue too.
I found a solution for this -

escodegen/escodegen.js

Lines 946 to 949 in ab53cd5

	expr = this.generateExpression(node.body, Precedence.Assignment, E_TTT);
	if (expr.toString().charAt(0) === '{') {
	expr = ['(', expr, ')'];
	}

this should be

var strExpr = expr.toString();
if (strExpr[0] === '{' || strExpr[strExpr.length - 1] === '}') {
  expr = ['(', expr, ')'];
}

I'm pretty sure the last character cannot be part of the comment, in that case the comment would not be part of the node

[lucivpav]

I wonder if this fix works for the affected parenthesized expressions in general, or just in function bodies 🤔

[Meir017]

@lucivpav a better solution is to check the node types:

if (node.type === Syntax.ArrowFunctionExpression && node.body.type === Syntax.ObjectExpression) {
  expr = ['(', expr, ')'];
}

[Itazulay]

@lucivpav This PR does not cover this scenario:
var a = b => ({}.hasOwnProperty.call(b, "c"));
This is a CallExpression and not an ObjectExpression.
Maybe it should be simply:
if (node.type === Syntax.ArrowFunctionExpression) { expr = ['(', expr, ')']; }

[lucivpav]

@Itazulay my new PR is implementing it properly IMO
https://github.com/estools/escodegen/pull/437/files#diff-f422139858ace4feaa93c12eac40aff386df95122af5cf2fc1874bf946ef8578R294