module.exports = Transformer;
var traverse = require("../traverse");
var t = require("../types");
var _ = require("lodash");
function Transformer(key, transformer) {
this.transformer = Transformer.normalise(transformer);
this.key = key;
}
Transformer.normalise = function (transformer) {
if (_.isFunction(transformer)) {
transformer = { ast: transformer };
}
_.each(transformer, function (fns, type) {
if (_.isFunction(fns)) fns = { enter: fns };
transformer[type] = fns;
});
return transformer;
};
Transformer.prototype.transform = function (file) {
if (!this.canRun(file)) return;
var transformer = this.transformer;
var ast = file.ast;
var astRun = function (key) {
if (transformer.ast && transformer.ast[key]) {
transformer.ast[key](ast, file);
}
};
astRun("enter");
var build = function (exit) {
return function (node, parent, scope) {
// add any node type aliases that exist
var types = [node.type].concat(t.ALIAS_KEYS[node.type] || []);
var fns = transformer.all;
_.each(types, function (type) {
fns = transformer[type] || fns;
});
// this transformer cannot deal with this node type
if (!fns) return;
var fn = fns.enter;
if (exit) fn = fns.exit;
if (!fn) return;
return fn(node, parent, file, scope);
};
};
traverse(ast, {
enter: build(),
exit: build(true)
});
astRun("exit");
};
Transformer.prototype.canRun = function (file) {
var opts = file.opts;
var key = this.key;
var blacklist = opts.blacklist;
if (blacklist.length && _.contains(blacklist, key)) return false;
if (key[0] !== "_") {
var whitelist = opts.whitelist;
if (whitelist.length && !_.contains(whitelist, key)) return false;
}
return true;
};
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