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'use strict';
Object.defineProperty(exports, "__esModule", {
value: true
});
exports.SecondPassIfVisitor = exports.FirstPassIfVisitor = undefined;
var _babelTypes = require('babel-types');
var _utils = require('./utils');
var _jsExtend = require('js-extend');
var FirstPassIfVisitor = exports.FirstPassIfVisitor = {
IfStatement: function IfStatement(path) {
var _this = this;
var node = path.node;
(0, _babelTypes.ensureBlock)(node, 'consequent');
if (node.alternate) {
(0, _babelTypes.ensureBlock)(node, 'alternate');
}
if (node.consequent.body.some(_babelTypes.isIfStatement) && containsReturnOrAwait(path)) {
(function () {
// flatten if statements. There are two ways to reach d() in the below.
// if a() && !b(), and if !a() && !b(). That's problematic during the
// promise conversion.
//
// if (a()) {
// if (b()) {
// return c();
// }
// }
// return d();
//
// this becomes instead:
//
// var _test = a();
// if (_test && b()) {
// return c();
// }
// return d();
//
// which is better, but not quite the result we want yet. See for that
// the BlockStatement handler in the other IfRefactorVisitor below.
var testID = (0, _babelTypes.identifier)(path.scope.generateUid('test'));
_this.addVarDecl(testID);
var block = [(0, _utils.assign)(testID, node.test)];
var stillToAdd = [];
var clearQueue = function clearQueue() {
if (stillToAdd.length) {
block.push((0, _babelTypes.ifStatement)(testID, (0, _babelTypes.blockStatement)(stillToAdd)));
stillToAdd = [];
}
};
node.consequent.body.forEach(function (stmt) {
if ((0, _babelTypes.isIfStatement)(stmt)) {
clearQueue();
stmt.test = (0, _babelTypes.logicalExpression)('&&', testID, stmt.test);
if (stmt.alternate) {
stmt.alternate = (0, _babelTypes.blockStatement)([(0, _babelTypes.ifStatement)(testID, stmt.alternate)]);
}
block.push(stmt);
} else {
stillToAdd.push(stmt);
}
});
clearQueue();
extendElse(block[block.length - 1], (node.alternate || {}).body || []);
path.replaceWithMultiple(block);
})();
}
}
};
var containsReturnOrAwait = (0, _utils.matcher)(['ReturnStatement', 'AwaitExpression'], _utils.NoSubFunctionsVisitor);
var SecondPassIfVisitor = exports.SecondPassIfVisitor = (0, _jsExtend.extend)({
IfStatement: function IfStatement(path) {
var alt = path.node.alternate;
if (!path.node.consequent.body.length && alt && alt.body.length) {
path.node.consequent = path.node.alternate;
path.node.alternate = null;
path.node.test = (0, _babelTypes.unaryExpression)('!', path.node.test);
}
var ifContainsAwait = (0, _utils.containsAwait)(path.get('consequent'));
var elseContainsAwait = (0, _utils.containsAwait)(path.get('alternate'));
var node = path.node;
if (ifContainsAwait) {
node.consequent = wrapIfBranch(node.consequent);
}
if (elseContainsAwait) {
node.alternate = wrapIfBranch(node.alternate);
}
if (ifContainsAwait || elseContainsAwait) {
path.replaceWith((0, _babelTypes.awaitExpression)((0, _utils.wrapFunction)((0, _babelTypes.blockStatement)([node]))));
}
},
BlockStatement: function BlockStatement(path) {
// Converts
//
// var _test = a();
// if (_test && b()) {
// return c();
// }
// return d();
//
// into:
//
// var _test = a();
// if (_test && b()) {
// return c();
// } else {
// return d();
// }
//
// ... which has at every point in time only two choices: returning
// directly out of the function, or continueing on. That's what's required
// for a nice conversion to Promise chains.
for (var i = 0; i < path.node.body.length; i++) {
var subNode = path.node.body[i];
if ((0, _babelTypes.isReturnStatement)(subNode)) {
// remove everything in the block after the return - it's never going
// to be executed anyway.
path.node.body.splice(i + 1);
}
if (!(0, _babelTypes.isIfStatement)(subNode)) {
continue;
}
var lastStmt = subNode.consequent.body[subNode.consequent.body.length - 1];
if (!(0, _babelTypes.isReturnStatement)(lastStmt)) {
continue;
}
var remainder = path.node.body.splice(i + 1);
if (!lastStmt.argument) {
// chop off the soon to be useless return statement
subNode.consequent.body.splice(-1);
}
extendElse(subNode, remainder);
}
}
}, _utils.NoSubFunctionsVisitor);
var wrapIfBranch = function wrapIfBranch(branch) {
return (0, _babelTypes.blockStatement)([(0, _babelTypes.returnStatement)((0, _utils.wrapFunction)(branch))]);
};
function extendElse(ifStmt, extraBody) {
var body = ((ifStmt.alternate || {}).body || []).concat(extraBody);
if (body.length) {
ifStmt.alternate = (0, _babelTypes.blockStatement)(body);
}
}
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