babel-core/lib/babel/generation/node/parentheses.js

Turn ES6 code into readable vanilla ES5 with source maps

"use strict";

var _interopRequireWildcard = function (obj) { return obj && obj.__esModule ? obj : { "default": obj }; };

var _interopRequire = function (obj) { return obj && obj.__esModule ? obj["default"] : obj; };

exports.NullableTypeAnnotation = NullableTypeAnnotation;
exports.UpdateExpression = UpdateExpression;
exports.ObjectExpression = ObjectExpression;
exports.Binary = Binary;
exports.BinaryExpression = BinaryExpression;
exports.SequenceExpression = SequenceExpression;
exports.YieldExpression = YieldExpression;
exports.ClassExpression = ClassExpression;
exports.UnaryLike = UnaryLike;
exports.FunctionExpression = FunctionExpression;
exports.ConditionalExpression = ConditionalExpression;
exports.__esModule = true;

var each = _interopRequire(require("lodash/collection/each"));

var t = _interopRequireWildcard(require("../../types"));

var PRECEDENCE = {};

each([["||"], ["&&"], ["|"], ["^"], ["&"], ["==", "===", "!=", "!=="], ["<", ">", "<=", ">=", "in", "instanceof"], [">>", "<<", ">>>"], ["+", "-"], ["*", "/", "%"], ["**"]], function (tier, i) {
  each(tier, function (op) {
    PRECEDENCE[op] = i;
  });
});

function NullableTypeAnnotation(node, parent) {
  return t.isArrayTypeAnnotation(parent);
}

exports.FunctionTypeAnnotation = NullableTypeAnnotation;

function UpdateExpression(node, parent) {
  if (t.isMemberExpression(parent) && parent.object === node) {
    // (foo++).test()
    return true;
  }
}

function ObjectExpression(node, parent) {
  if (t.isExpressionStatement(parent)) {
    // ({ foo: "bar" });
    return true;
  }

  if (t.isMemberExpression(parent) && parent.object === node) {
    // ({ foo: "bar" }).foo
    return true;
  }

  return false;
}

function Binary(node, parent) {
  if ((t.isCallExpression(parent) || t.isNewExpression(parent)) && parent.callee === node) {
    return true;
  }

  if (t.isUnaryLike(parent)) {
    return true;
  }

  if (t.isMemberExpression(parent) && parent.object === node) {
    return true;
  }

  if (t.isBinary(parent)) {
    var parentOp = parent.operator;
    var parentPos = PRECEDENCE[parentOp];

    var nodeOp = node.operator;
    var nodePos = PRECEDENCE[nodeOp];

    if (parentPos > nodePos) {
      return true;
    }

    if (parentPos === nodePos && parent.right === node) {
      return true;
    }
  }
}

function BinaryExpression(node, parent) {
  if (node.operator === "in") {
    // var i = (1 in []);
    if (t.isVariableDeclarator(parent)) {
      return true;
    }

    // for ((1 in []);;);
    if (t.isFor(parent)) {
      return true;
    }
  }
}

function SequenceExpression(node, parent) {
  if (t.isForStatement(parent)) {
    // Although parentheses wouldn't hurt around sequence
    // expressions in the head of for loops, traditional style
    // dictates that e.g. i++, j++ should not be wrapped with
    // parentheses.
    return false;
  }

  if (t.isExpressionStatement(parent) && parent.expression === node) {
    return false;
  }

  // Otherwise err on the side of overparenthesization, adding
  // explicit exceptions above if this proves overzealous.
  return true;
}

function YieldExpression(node, parent) {
  return t.isBinary(parent) || t.isUnaryLike(parent) || t.isCallExpression(parent) || t.isMemberExpression(parent) || t.isNewExpression(parent) || t.isConditionalExpression(parent) || t.isYieldExpression(parent);
}

function ClassExpression(node, parent) {
  return t.isExpressionStatement(parent);
}

function UnaryLike(node, parent) {
  return t.isMemberExpression(parent) && parent.object === node;
}

function FunctionExpression(node, parent) {
  // function () {};
  if (t.isExpressionStatement(parent)) {
    return true;
  }

  // (function test() {}).name;
  if (t.isMemberExpression(parent) && parent.object === node) {
    return true;
  }

  // (function () {})();
  if (t.isCallExpression(parent) && parent.callee === node) {
    return true;
  }
}

function ConditionalExpression(node, parent) {
  if (t.isUnaryLike(parent)) {
    return true;
  }

  if (t.isBinary(parent)) {
    return true;
  }

  if (t.isCallExpression(parent) || t.isNewExpression(parent)) {
    if (parent.callee === node) {
      return true;
    }
  }

  if (t.isConditionalExpression(parent) && parent.test === node) {
    return true;
  }

  if (t.isMemberExpression(parent) && parent.object === node) {
    return true;
  }

  return false;
}

exports.AssignmentExpression = ConditionalExpression;