feat(core): implement plugin api

packages/bbob-core/lib/utils.js

@@ -0,0 +1,65 @@
+/* eslint-disable no-plusplus */
+const isObj = value => (typeof value === 'object');
+const isBool = value => (typeof value === 'boolean');
+
+function iterate(t, cb) {
+  const tree = t;
+
+  if (Array.isArray(tree)) {
+    for (let idx = 0; idx < tree.length; idx++) {
+      tree[idx] = iterate(cb(tree[idx]), cb);
+    }
+  } else if (tree && isObj(tree) && tree.content) {
+    iterate(tree.content, cb);
+  }
+
+  return tree;
+}
+
+function same(expected, actual) {
+  if (typeof expected !== typeof actual) {
+    return false;
+  }
+
+  if (!isObj(expected) || expected === null) {
+    return expected === actual;
+  }
+
+  if (Array.isArray(expected)) {
+    return expected.every(exp => [].some.call(actual, act => same(exp, act)));
+  }
+
+  return Object.keys(expected).every((key) => {
+    const ao = actual[key];
+    const eo = expected[key];
+
+    if (isObj(eo) && eo !== null && ao !== null) {
+      return same(eo, ao);
+    }
+
+    if (isBool(eo)) {
+      return eo !== (ao === null);
+    }
+
+    return ao === eo;
+  });
+}
+
+function match(expression, cb) {
+  return Array.isArray(expression)
+    ? iterate(this, (node) => {
+      for (let idx = 0; idx < expression.length; idx++) {
+        if (same(expression[idx], node)) {
+          return cb(node);
+        }
+      }
+
+      return node;
+    })
+    : iterate(this, node => (same(expression, node) ? cb(node) : node));
+}
+
+module.exports = {
+  iterate,
+  match,
+};