优化翻译

.stfolder/syncthing-folder-ed52c7.txt

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+# This directory is a Syncthing folder marker.
+# Do not delete.
+
+folderID: zh.javascript.info
+created: 2024-09-17T00:54:09+08:00

.stignore

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+.git

.vscode/launch.json

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+{
+    // Use IntelliSense to learn about possible attributes.
+    // Hover to view descriptions of existing attributes.
+    // For more information, visit: https://go.microsoft.com/fwlink/?linkid=830387
+    "version": "0.2.0",
+    "configurations": [
+        {
+            "name": "Launch Chrome",
+            "request": "launch",
+            "type": "chrome",
+            "url": "http://localhost:8080",
+            "webRoot": "${workspaceFolder}"
+        },
+        {
+            "type": "node",
+            "request": "launch",
+            "name": "Launch Program",
+            "skipFiles": [
+                "<node_internals>/**"
+            ],
+            "program": "${file}"
+        }
+    ]
+}

.vscode/tasks.json

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+{
+    // See https://go.microsoft.com/fwlink/?LinkId=733558
+    // for the documentation about the tasks.json format
+    "version": "2.0.0",
+    "tasks": [
+        {
+            "label": "echo",
+            "type": "shell",
+            "command": "echo Hello ${file}"
+        },
+        {
+            "label": "replace ALERT",
+            "type": "shell",
+            "command": "d:\\git\\usr\\bin\\sed -i 's/alert/console.log/g' ${file}"
+        },
+        {
+            "label": "gvim",
+            "type": "shell",
+            "command": "D:/Vim/vim91/gvim.exe ${file}"
+        }
+        {
+            "label": "git add",
+            "type": "shell",
+            "command": "D:/Git/mingw64/libexec/git-core/git.exe add ${file}"
+        }
+    ]
+}

1-js/05-data-types/03-string/1.js

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+
+let str = 'Hi';
+
+str[0] = 'h'; // error
+console.log( str[0] ); // 不成功

1-js/05-data-types/03-string/article.md

@@ -186,7 +186,7 @@ for (let char of "Hello") {
 let str = 'Hi';
 
 str[0] = 'h'; // error
-alert( str[0] ); // 无法运行
+alert( str[0] ); // 没成功
 ```
 
 通常的解决方法是创建一个新的字符串，并将其分配给 `str` 而不是以前的字符串。

1-js/05-data-types/04-array/test.js

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+
+console.log(1);
+console.log(2);

1-js/05-data-types/05-array-methods/1.js

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+
+let army = {
+  minAge: 18,
+  maxAge: 27,
+  canJoin(user) {
+    return user.age >= this.minAge && user.age < this.maxAge;
+  }
+};
+
+let users = [
+  {age: 16},
+  {age: 20},
+  {age: 23},
+  {age: 30}
+];
+
+// 找到 army.canJoin 返回 true 的 user
+let soldiers = users.filter(army.canJoin, army);
+
+console.log(soldiers.length); // 2
+console.log(soldiers[0].age); // 20
+console.log(soldiers[1].age); // 23

1-js/05-data-types/08-weakmap-weakset/1.js

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+
+let john = { name: "John" };
+
+let weakMap = new WeakMap();
+weakMap.set(john, "...");
+
+john = null; // 覆盖引用
+
+console.log(weakMap);
+// WeakMap { <items unknown> }
+
+// console.log(weakMap.get())
+
+// john 被从内存中删除了！

1-js/05-data-types/12-json/1.js

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+

1-js/06-advanced-functions/06-function-object/1.js

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+
+let sayHi = function() {
+    console.log("Hi");
+  };
+
+  console.log(sayHi);
+  console.log(sayHi.name); // sayHi（有名字！）
+
+  let aaa = sayHi;
+  console.log(aaa); // still sayHi, sure.
+  aaa();
+
+  let qqq = function(){
+    console.log("q");
+  };
+  console.log(qqq.name);
+
+  let ann = () => { console.log("a"); };
+  console.log(ann.name);
+  ann();

1-js/06-advanced-functions/06-function-object/func-obj1.js

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+
+function sayHi() {
+  console.log("Hi");
+
+  // 计算调用次数
+  sayHi.counter++;
+}
+sayHi.counter = 0; // 初始值
+
+sayHi(); // Hi
+sayHi(); // Hi
+
+console.log( `Called ${sayHi.counter} times` ); // Called 2 times

1-js/06-advanced-functions/06-function-object/func-obj2.js

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+
+function makeCounter() {
+  // 不需要这个了
+  // let count = 0
+
+  function counter() {
+    return counter.count++;
+  };
+
+  counter.count = 0;
+
+  return counter;
+}
+
+let ct = makeCounter();
+console.log( ct() ); // 0
+console.log( ct() ); // 1

1-js/06-advanced-functions/08-settimeout-setinterval/timeout1.js

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+
+let start = Date.now();
+let times = [];
+
+setTimeout(function run() {
+  times.push(Date.now() - start); // 保存前一个调用的延时
+
+  if (start + 100 < Date.now()) console.log(times); // 100 毫秒之后，显示延时信息
+  else setTimeout(run); // 否则重新调度
+});

1-js/06-advanced-functions/09-call-apply-decorators/deco0.js

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+
+function slow(x) {
+  // 这里可能会有重负载的 CPU 密集型工作
+  console.log(`Called with ${x}`);
+  return x;
+}
+
+function cachingDecorator(func) {
+  let cache = new Map();
+
+  return function(x) {
+    if (cache.has(x)) {    // 如果缓存中有对应的结果
+      return cache.get(x); // 从缓存中读取结果
+    }
+
+    let result = func(x);  // 否则就调用 func
+
+    cache.set(x, result);  // 然后将结果缓存（记住）下来
+    return result;
+  };
+}
+
+slow = cachingDecorator(slow);
+
+console.log( slow(1) ); // slow(1) 被缓存下来了，并返回结果
+console.log( "Again: " + slow(1) ); // 返回缓存中的 slow(1) 的结果
+
+console.log( slow(2) ); // slow(2) 被缓存下来了，并返回结果
+console.log( "Again: " + slow(2) ); // 返回缓存中的 slow(2) 的结果

1-js/06-advanced-functions/09-call-apply-decorators/deco1.js

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+
+let worker = {
+
+  someMethod() {
+    return 1;
+  },
+
+  slow(x) {
+    // 可怕的 CPU 过载任务
+    console.log("Called with " + x);
+    return x * this.someMethod(); // (*)
+  }
+
+};
+
+// 和之前例子中的代码相同
+function cachingDecorator(func) {
+  let cache = new Map();
+  return function(x) {
+    if (cache.has(x)) {
+      return cache.get(x);
+    }
+
+    let result = func(x); // (**)
+    cache.set(x, result);
+    return result;
+  };
+}
+
+console.log( worker.slow(1) ); // 原始方法有效
+
+worker.slow = cachingDecorator(worker.slow); // 现在对其进行缓存
+
+console.log( worker.slow(2) ); // 蛤！Error: Cannot read property 'someMethod' of undefined

1-js/06-advanced-functions/10-bind/bind1.js

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+
+let user = {
+  firstName: "John"
+};
+
+function f1() {
+  console.log(this.firstName);
+}
+
+let funcUser = f1.bind(user);
+funcUser(); // John  

1-js/07-object-properties/01-property-descriptors/prop-desc-config.js

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+
+console.log(Math.PI);
+
+let descriptor = Object.getOwnPropertyDescriptor(Math, 'PI');
+
+console.log( JSON.stringify(descriptor, null, 2 ) );
+/*
+{
+  "value": 3.141592653589793,
+  "writable": false,
+  "enumerable": false,
+  "configurable": false
+}
+*/
+
+Math.PI = 3; // Error，因为其 writable: false
+
+console.log(Math.PI);
+// 3.141592653589793
+
+// Error，因为 configurable: false
+// Object.defineProperty(Math, "PI", { writable: true });
+// TypeError: Cannot redefine property: PI
+
+
+
+
+let user = {
+  name: "John"
+};
+
+Object.defineProperty(user, "name", {
+  configurable: false
+});
+
+user.name = "Pete"; // 正常工作
+console.log(user);
+// { name: 'Pete' }
+
+delete user.name; // Error
+console.log(user);
+// { name: 'Pete' }

1-js/07-object-properties/01-property-descriptors/prop-desc.js

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+
+let user = {
+  name: "John"
+};
+
+let descriptor = Object.getOwnPropertyDescriptor(user, 'name');
+
+console.log( JSON.stringify(descriptor, null, 2 ) );
+/* 属性描述符：
+{
+  "value": "John",
+  "writable": true,
+  "enumerable": true,
+  "configurable": true
+}
+*/

1-js/07-object-properties/01-property-descriptors/prop-desc2.js

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+
+let user = {};
+
+Object.defineProperty(user, "name", {
+  value: "John"
+});
+
+let descriptor = Object.getOwnPropertyDescriptor(user, 'name');
+
+console.log( JSON.stringify(descriptor, null, 2 ) );
+/*
+{
+  "value": "John",
+  "writable": false,
+  "enumerable": false,
+  "configurable": false
+}
+ */
+
+console.log(user);
+// {} 
+
+
+Object.defineProperty(user, "addr", {
+  value: "221B",
+  enumerable: true,
+});
+console.log(user);
+// { addr: '221B' }
+
+user.name = "rose";
+// no effect
+console.log(user);
+// { addr: '221B' }
+
+user.addr="13F"
+// no effect
+console.log(user);
+// { addr: '221B' }
+
+Object.defineProperty(user, "nick", {
+  value: "nnn",
+  enumerable: true,
+//   configurable: true,
+    writable: true,
+});
+console.log(user);
+// { addr: '221B', nick: 'nnn' }
+
+user.nick="mmm";
+console.log(user);
+// { addr: '221B', nick: 'mmm' }
+
+Object.defineProperty(user, "ROAttr", {
+    value : "init val",
+    enumerable: true,
+    writable: false,
+});
+console.log(user);
+// { addr: '221B', nick: 'mmm', ROAttr: 'init val' }
+user.ROAttr = "failing change";
+console.log(user);
+// { addr: '221B', nick: 'mmm', ROAttr: 'init val' }