LibJS: Add JSON.parse

Libraries/LibJS/Tests/JSON.parse-reviver.js

@@ -0,0 +1,15 @@
+load("test-common.js");
+
+try {
+    let string = `{"var1":10,"var2":"hello","var3":{"nested":5}}`;
+
+    let object = JSON.parse(string, (key, value) => typeof value === "number" ? value * 2 : value);
+    assertDeepEquals(object, { var1: 20, var2: "hello", var3: { nested: 10 } });
+
+    object = JSON.parse(string, (key, value) => typeof value === "number" ? undefined : value);
+    assertDeepEquals(object, { var2: "hello", var3: {} });
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}

Libraries/LibJS/Tests/JSON.parse.js

@@ -0,0 +1,43 @@
+load("test-common.js");
+
+try {
+    assert(JSON.parse.length === 2);
+
+    const properties = [
+        ["5", 5],
+        ["null", null],
+        ["true", true],
+        ["false", false],
+        ['"test"', "test"],
+        ['[1,2,"foo"]', [1, 2, "foo"]],
+        ['{"foo":1,"bar":"baz"}', { foo: 1, bar: "baz" }],
+    ];
+
+    properties.forEach(testCase => {
+        assertDeepEquals(JSON.parse(testCase[0]), testCase[1]);
+    });
+
+    let syntaxErrors = [
+        undefined,
+        NaN,
+        -NaN,
+        Infinity,
+        -Infinity,
+        '{ "foo" }',
+        '{ foo: "bar" }',
+        "[1,2,3,]",
+        "[1,2,3, ]",
+        '{ "foo": "bar",}',
+        '{ "foo": "bar", }',
+    ];
+
+    syntaxErrors.forEach(error => assertThrowsError(() => {
+        JSON.parse(error);
+    }, {
+        error: SyntaxError,
+    }));
+
+    console.log("PASS");
+} catch (e) {
+    console.log("FAIL: " + e);
+}

Libraries/LibJS/Tests/test-common.js

@@ -92,3 +92,40 @@ const assertVisitsAll = (testFunction, expectedOutput) => {
 function isClose(a, b) {
     return Math.abs(a - b) < 0.000001;
 }
+
+/**
+ * Quick and dirty deep equals method.
+ * @param {*} a First value
+ * @param {*} b Second value
+ */
+function assertDeepEquals(a, b) {
+    assert(deepEquals(a, b));
+}
+
+function deepEquals(a, b) {
+    if (Array.isArray(a))
+        return Array.isArray(b) && deepArrayEquals(a, b);
+    if (typeof a === "object")
+        return typeof b === "object" && deepObjectEquals(a, b);
+    return a === b;
+}
+
+function deepArrayEquals(a, b) {
+    if (a.length !== b.length)
+        return false;
+    for (let i = 0; i < a.length; ++i) {
+        if (!deepEquals(a[i], b[i]))
+            return false;
+    }
+    return true;
+}
+
+function deepObjectEquals(a, b) {
+    if (a === null)
+        return b === null;
+    for (let key of Reflect.ownKeys(a)) {
+        if (!deepEquals(a[key], b[key]))
+            return false;
+    }
+    return true;
+}