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151 lines
4.8 KiB
JavaScript

6 years ago
"use strict";
var _keys = require("babel-runtime/core-js/object/keys");
var _keys2 = _interopRequireDefault(_keys);
var _babelTypes = require("babel-types");
var t = _interopRequireWildcard(_babelTypes);
var _util = require("./util");
var util = _interopRequireWildcard(_util);
function _interopRequireWildcard(obj) { if (obj && obj.__esModule) { return obj; } else { var newObj = {}; if (obj != null) { for (var key in obj) { if (Object.prototype.hasOwnProperty.call(obj, key)) newObj[key] = obj[key]; } } newObj.default = obj; return newObj; } }
function _interopRequireDefault(obj) { return obj && obj.__esModule ? obj : { default: obj }; }
/**
* Copyright (c) 2014, Facebook, Inc.
* All rights reserved.
*
* This source code is licensed under the BSD-style license found in the
* https://raw.github.com/facebook/regenerator/master/LICENSE file. An
* additional grant of patent rights can be found in the PATENTS file in
* the same directory.
*/
var hasOwn = Object.prototype.hasOwnProperty;
// The hoist function takes a FunctionExpression or FunctionDeclaration
// and replaces any Declaration nodes in its body with assignments, then
// returns a VariableDeclaration containing just the names of the removed
// declarations.
exports.hoist = function (funPath) {
t.assertFunction(funPath.node);
var vars = {};
function varDeclToExpr(vdec, includeIdentifiers) {
t.assertVariableDeclaration(vdec);
// TODO assert.equal(vdec.kind, "var");
var exprs = [];
vdec.declarations.forEach(function (dec) {
// Note: We duplicate 'dec.id' here to ensure that the variable declaration IDs don't
// have the same 'loc' value, since that can make sourcemaps and retainLines behave poorly.
vars[dec.id.name] = t.identifier(dec.id.name);
if (dec.init) {
exprs.push(t.assignmentExpression("=", dec.id, dec.init));
} else if (includeIdentifiers) {
exprs.push(dec.id);
}
});
if (exprs.length === 0) return null;
if (exprs.length === 1) return exprs[0];
return t.sequenceExpression(exprs);
}
funPath.get("body").traverse({
VariableDeclaration: {
exit: function exit(path) {
var expr = varDeclToExpr(path.node, false);
if (expr === null) {
path.remove();
} else {
// We don't need to traverse this expression any further because
// there can't be any new declarations inside an expression.
util.replaceWithOrRemove(path, t.expressionStatement(expr));
}
// Since the original node has been either removed or replaced,
// avoid traversing it any further.
path.skip();
}
},
ForStatement: function ForStatement(path) {
var init = path.node.init;
if (t.isVariableDeclaration(init)) {
util.replaceWithOrRemove(path.get("init"), varDeclToExpr(init, false));
}
},
ForXStatement: function ForXStatement(path) {
var left = path.get("left");
if (left.isVariableDeclaration()) {
util.replaceWithOrRemove(left, varDeclToExpr(left.node, true));
}
},
FunctionDeclaration: function FunctionDeclaration(path) {
var node = path.node;
vars[node.id.name] = node.id;
var assignment = t.expressionStatement(t.assignmentExpression("=", node.id, t.functionExpression(node.id, node.params, node.body, node.generator, node.expression)));
if (path.parentPath.isBlockStatement()) {
// Insert the assignment form before the first statement in the
// enclosing block.
path.parentPath.unshiftContainer("body", assignment);
// Remove the function declaration now that we've inserted the
// equivalent assignment form at the beginning of the block.
path.remove();
} else {
// If the parent node is not a block statement, then we can just
// replace the declaration with the equivalent assignment form
// without worrying about hoisting it.
util.replaceWithOrRemove(path, assignment);
}
// Don't hoist variables out of inner functions.
path.skip();
},
FunctionExpression: function FunctionExpression(path) {
// Don't descend into nested function expressions.
path.skip();
}
});
var paramNames = {};
funPath.get("params").forEach(function (paramPath) {
var param = paramPath.node;
if (t.isIdentifier(param)) {
paramNames[param.name] = param;
} else {
// Variables declared by destructuring parameter patterns will be
// harmlessly re-declared.
}
});
var declarations = [];
(0, _keys2.default)(vars).forEach(function (name) {
if (!hasOwn.call(paramNames, name)) {
declarations.push(t.variableDeclarator(vars[name], null));
}
});
if (declarations.length === 0) {
return null; // Be sure to handle this case!
}
return t.variableDeclaration("var", declarations);
};