babel/lib/6to5/traverse/scope.js

120 lines
2.7 KiB
JavaScript

module.exports = Scope;
var traverse = require("./index");
var t = require("../types");
var _ = require("lodash");
var FOR_KEYS = ["left", "init"];
function Scope(parent, block) {
this.parent = parent;
this.block = block;
this.info = this.getInfo();
this.declarations = this.info.declarations;
this.references = this.info.references;
}
Scope.prototype.getInfo = function () {
var block = this.block;
if (block._scope) return block._scope;
var self = this;
var info = block._scope = {
declarations: {}
};
var add = function (node) {
self.addDeclaration(node, info.declarations);
};
// ForStatement - left, init
if (t.isFor(block)) {
_.each(FOR_KEYS, function (key) {
var node = block[key];
if (t.isLet(node)) add(node);
});
block = block.body;
}
// Program, BlockStatement - let variables
if (t.isBlockStatement(block) || t.isProgram(block)) {
_.each(block.body, function (node) {
// check for non-var `VariableDeclaration`s
if (t.isLet(node)) add(node);
});
}
// CatchClause - param
if (t.isCatchClause(block)) {
add(block.param);
}
// Program, Function - var variables
if (t.isProgram(block) || t.isFunction(block)) {
traverse(block, function (node) {
if (t.isFor(node)) {
_.each(FOR_KEYS, function (key) {
var declar = node[key];
if (t.isVar(declar)) add(declar);
});
}
// this block is a function so we'll stop since none of the variables
// declared within are accessible
if (t.isFunction(node)) return false;
// we've ran into a declaration!
// we'll let the BlockStatement scope deal with `let` declarations
if (t.isDeclaration(node) && !t.isLet(node)) {
add(node);
}
});
}
// Function - params, rest
if (t.isFunction(block)) {
add(block.rest);
_.each(block.params, function (param) {
add(param);
});
}
return info;
};
Scope.prototype.addDeclaration = function (node, declarations) {
if (!node) return;
_.merge(declarations || this.declarations, t.getIds(node, true));
};
Scope.prototype.get = function (id) {
return id && (this.getOwn(id) || this.parentGet(id));
};
Scope.prototype.getOwn = function (id) {
return _.has(this.declarations, id) && this.declarations[id];
};
Scope.prototype.parentGet = function (id) {
return this.parent && this.parent.get(id);
};
Scope.prototype.has = function (id) {
return id && (this.hasOwn(id) || this.parentHas(id));
};
Scope.prototype.hasOwn = function (id) {
return !!this.getOwn(id);
};
Scope.prototype.parentHas = function (id) {
return this.parent && this.parent.has(id);
};