babel/lib/6to5/generation/node/parentheses.js
Sebastian McKenzie af59eb7d6a fix linting errors
2014-11-12 00:33:39 +11:00

151 lines
3.2 KiB
JavaScript

var t = require("../../types");
var _ = require("lodash");
var PRECEDENCE = {};
_.each([
["||"],
["&&"],
["|"],
["^"],
["&"],
["==", "===", "!=", "!=="],
["<", ">", "<=", ">=", "in", "instanceof"],
[">>", "<<", ">>>"],
["+", "-"],
["*", "/", "%"]
], function (tier, i) {
_.each(tier, function (op) {
PRECEDENCE[op] = i;
});
});
exports.Binary = function (node, parent) {
if (t.isCallExpression(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;
}
}
};
exports.BinaryExpression = function (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;
}
}
};
exports.SequenceExpression = function (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;
};
exports.YieldExpression = function (node, parent) {
return t.isBinary(parent) ||
t.isUnaryLike(parent) ||
t.isCallExpression(parent) ||
t.isMemberExpression(parent) ||
t.isNewExpression(parent) ||
t.isConditionalExpression(parent) ||
t.isYieldExpression(parent);
};
exports.Literal = function (node, parent) {
// (1).valueOf()
if (_.isNumber(node.value) && t.isMemberExpression(parent) && parent.object === node) {
return true;
}
};
exports.ClassExpression = function (node, parent) {
return t.isExpressionStatement(parent);
};
exports.UnaryLike = function (node, parent) {
return t.isMemberExpression(parent) && parent.object === node;
};
exports.FunctionExpression = function (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;
}
};
exports.AssignmentExpression =
exports.ConditionalExpression = function (node, parent) {
if (t.isUnaryLike(parent)) {
return true;
}
if (t.isBinary(parent)) {
return true;
}
if (t.isCallExpression(parent) && 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;
};