babel/lib/6to5/transformation/transformer.js
2015-01-17 00:13:39 +03:00

101 lines
2.4 KiB
JavaScript

module.exports = Transformer;
var traverse = require("../traverse");
var t = require("../types");
var _ = require("lodash");
function noop() { }
function enter(node, parent, scope, context, args) {
var fns = args[1][node.type];
if (!fns) return;
return fns.enter(node, parent, scope, context, args[0]);
}
function exit(node, parent, scope, context, args) {
var fns = args[1][node.type];
if (!fns) return;
return fns.exit(node, parent, scope, context, args[0]);
}
var traverseOpts = {
enter: enter,
exit: exit
};
function Transformer(key, transformer, opts) {
this.manipulateOptions = transformer.manipulateOptions;
this.experimental = !!transformer.experimental;
this.secondPass = !!transformer.secondPass;
this.transformer = this.normalise(transformer);
this.optional = !!transformer.optional;
this.opts = opts || {};
this.key = key;
}
Transformer.prototype.normalise = function (transformer) {
var self = this;
if (_.isFunction(transformer)) {
transformer = { ast: transformer };
}
_.each(transformer, function (fns, type) {
// hidden property
if (type[0] === "_") {
self[type] = fns;
return;
}
if (_.isFunction(fns)) fns = { enter: fns };
if (!_.isObject(fns)) return;
if (!fns.enter) fns.enter = noop;
if (!fns.exit) fns.exit = noop;
transformer[type] = fns;
var aliases = t.FLIPPED_ALIAS_KEYS[type];
if (aliases) {
_.each(aliases, function (alias) {
transformer[alias] = fns;
});
}
});
return transformer;
};
Transformer.prototype.astRun = function (file, key) {
var transformer = this.transformer;
if (transformer.ast && transformer.ast[key]) {
transformer.ast[key](file.ast, file);
}
};
Transformer.prototype.transform = function (file) {
this.astRun(file, "before");
traverse(file.ast, traverseOpts, null, [file, this.transformer]);
this.astRun(file, "after");
};
Transformer.prototype.canRun = function (file) {
var opts = file.opts;
var key = this.key;
if (key[0] === "_") return true;
var blacklist = opts.blacklist;
if (blacklist.length && _.contains(blacklist, key)) return false;
var whitelist = opts.whitelist;
if (whitelist.length && !_.contains(whitelist, key)) return false;
if (this.optional && !_.contains(opts.optional, key)) return false;
if (this.experimental && !opts.experimental) return false;
return true;
};