Merge pull request #555 from streamich/json-walk

json-walk

Author: streamich

package.json

@@ -236,6 +236,7 @@
           "json-text",
           "json-type",
           "json-type-value",
+          "json-walk",
           "reactive-rpc",
           "util"
         ]

src/json-walk/__tests__/index.spec.ts

@@ -0,0 +1,55 @@
+import {walk} from '..';
+
+test('can walk through a value', () => {
+  const value = {
+    a: 1,
+    foo: [2, 'a', null, 3, true, false, new Set([1, 2]), new Map([['b', 3]])],
+  };
+  const nodes: unknown[] = [];
+  walk(value, (node) => {
+    nodes.push(node);
+  });
+  expect(nodes).toEqual([
+    value,
+    1,
+    value.foo,
+    2,
+    'a',
+    null,
+    3,
+    true,
+    false,
+    new Set([1, 2]),
+    1,
+    2,
+    new Map([['b', 3]]),
+    3,
+  ]);
+});
+
+test('can walk through null', () => {
+  const value = null;
+  const nodes: unknown[] = [];
+  walk(value, (node) => {
+    nodes.push(node);
+  });
+  expect(nodes).toEqual([null]);
+});
+
+test('can walk empty object', () => {
+  const value = {};
+  const nodes: unknown[] = [];
+  walk(value, (node) => {
+    nodes.push(node);
+  });
+  expect(nodes).toEqual([{}]);
+});
+
+test('can walk empty array', () => {
+  const value: any[] = [];
+  const nodes: unknown[] = [];
+  walk(value, (node) => {
+    nodes.push(node);
+  });
+  expect(nodes).toEqual([[]]);
+});

src/json-walk/index.ts

@@ -0,0 +1,25 @@
+export const walk = (value: unknown, callback: (value: unknown) => void): void => {
+  callback(value);
+  if (typeof value === 'object') {
+    if (!value) return;
+    switch (value.constructor) {
+      case Array: {
+        const arr = value as unknown[];
+        const length = arr.length;
+        for (let i = 0; i < length; i++) walk(arr[i], callback);
+        break;
+      }
+      case Object: {
+        const obj = value as Record<string, unknown>;
+        for (const key in obj) walk(obj[key], callback);
+        break;
+      }
+      case Map:
+      case Set: {
+        const mapOrSet = value as Set<unknown> | Map<unknown, unknown>;
+        mapOrSet.forEach((val) => walk(val, callback));
+        break;
+      }
+    }
+  }
+};