javascript - Google Closure Annotating 不会告诉我我错了

Question

我正在试用 Google Closure，特别是用于强制类型安全的注释内容。为了测试我做错了什么，尽管编译器不会告诉我这是...

代码如下:

// ==ClosureCompiler==
// @output_file_name default.js
// @compilation_level SIMPLE_OPTIMIZATIONS
// ==/ClosureCompiler==

/**
 * A card.
 * @constructor
 * @param {String} cardName The exact name of the card
 * @param {Kinetic.Layer} layer The layer for the card
 */
function CardObject(cardName, layer)
{
    /** @type {Number} */
    var number = cardName;
}

因此，我有一个变量 number，我说它是一个 Number，我尝试为其分配一个字符串。这应该不可能吧？虽然编译器不会告诉我...

为什么它不告诉我这是错误的？

Answer 1

闭包编译器使用 warning levels以确定在编译过程中启用了哪些检查。三个警告级别是:

• 安静
• 默认
• 详细

例如，使用编译级别 SIMPLE_OPTIMIZATIONS，您仍然会收到警告级别设置为 VERBOSE 的类型检查警告。

// ==ClosureCompiler==
// @output_file_name default.js
// @compilation_level SIMPLE_OPTIMIZATIONS
// @warning_level VERBOSE
// ==/ClosureCompiler==

/**
 * A card.
 * @constructor
 * @param {String} cardName The exact name of the card
 * @param {Kinetic.Layer} layer The layer for the card
 */
function CardObject(cardName, layer)
{
    /** @type {Number} */
    var number = cardName;
}

输出

Number of warnings: 2

JSC_TYPE_PARSE_ERROR: Bad type annotation. Unknown type Kinetic.Layer at line 5
character 10  
* @param {Kinetic.Layer} layer The layer for the card
          ^
JSC_TYPE_MISMATCH: initializing variable
found   : (String|null|undefined)
required: (Number|null) at line 10 character 13
var number = cardName;
             ^

要准确了解哪些检查与每个警告级别相关联，这里是 WarningLevels.java 中的相关代码。

安静

/**
 * Silence all non-essential warnings.
 */
private static void silenceAllWarnings(CompilerOptions options) {
  // Just use a ShowByPath warnings guard, so that we don't have
  // to maintain a separate class of warnings guards for silencing warnings.
  options.addWarningsGuard(
      new ShowByPathWarningsGuard(
          "the_longest_path_that_cannot_be_expressed_as_a_string"));

  // Allow passes that aren't going to report anything to be skipped.

  options.checkRequires = CheckLevel.OFF;
  options.checkProvides = CheckLevel.OFF;
  options.checkMissingGetCssNameLevel = CheckLevel.OFF;
  options.aggressiveVarCheck = CheckLevel.OFF;
  options.checkTypes = false;
  options.setWarningLevel(DiagnosticGroups.CHECK_TYPES, CheckLevel.OFF);
  options.checkUnreachableCode = CheckLevel.OFF;
  options.checkMissingReturn = CheckLevel.OFF;
  options.setWarningLevel(DiagnosticGroups.ACCESS_CONTROLS, CheckLevel.OFF);
  options.setWarningLevel(DiagnosticGroups.CONST, CheckLevel.OFF);
  options.setWarningLevel(DiagnosticGroups.CONSTANT_PROPERTY, CheckLevel.OFF);
  options.checkGlobalNamesLevel = CheckLevel.OFF;
  options.checkSuspiciousCode = false;
  options.checkGlobalThisLevel = CheckLevel.OFF;
  options.setWarningLevel(DiagnosticGroups.GLOBAL_THIS, CheckLevel.OFF);
  options.setWarningLevel(DiagnosticGroups.ES5_STRICT, CheckLevel.OFF);
  options.checkCaja = false;
}

默认

/**
 * Add the default checking pass to the compilation options.
 * @param options The CompilerOptions object to set the options on.
 */
private static void addDefaultWarnings(CompilerOptions options) {
  options.checkSuspiciousCode = true;
  options.checkUnreachableCode = CheckLevel.WARNING;
  options.checkControlStructures = true;
}

冗长

/**
 * Add all the check pass that are possibly relevant to a non-googler.
 * @param options The CompilerOptions object to set the options on.
 */
private static void addVerboseWarnings(CompilerOptions options) {
  addDefaultWarnings(options);

  // checkSuspiciousCode needs to be enabled for CheckGlobalThis to get run.
  options.checkSuspiciousCode = true;
  options.checkGlobalThisLevel = CheckLevel.WARNING;
  options.checkSymbols = true;
  options.checkMissingReturn = CheckLevel.WARNING;

  // checkTypes has the side-effect of asserting that the
  // correct number of arguments are passed to a function.
  // Because the CodingConvention used with the web service does not provide a
  // way for optional arguments to be specified, these warnings may result in
  // false positives.
  options.checkTypes = true;
  options.checkGlobalNamesLevel = CheckLevel.WARNING;
  options.aggressiveVarCheck = CheckLevel.WARNING;
  options.setWarningLevel(
      DiagnosticGroups.MISSING_PROPERTIES, CheckLevel.WARNING);
  options.setWarningLevel(
      DiagnosticGroups.DEPRECATED, CheckLevel.WARNING);
}

请注意，options.checkTypes = true; 仅为 VERBOSE 警告级别设置。作为Speransky Danil指出，使用编译级别 ADVANCED_OPTIMIZATIONS 时也会启用类型检查。

此外，可以使用编译器标志通过 Closure 编译器应用程序(jar 文件)单独控制警告类别:

• --jscomp_off
• --jscomp_warning
• --jscomp_error

可以指定的警告类如下:

• 访问控制
• 模棱两可的函数声明
• 检查正则表达式
• 检查类型
• 检查变量
• 常量
• 常量属性
• 已弃用
• 复制消息
• es5严格
• 外部验证
• 文件概览标签
• globalThis
• internetExplorerChecks
• 无效的转换
• 缺少属性
• 非StandardJsDocs
• strictModuleDepCheck
• 类型失效
• undefinedNames
• undefined variable
• 未知定义
• 无用代码
• 知名度

例如，可以单独启用类型检查警告:

--jscomp_warning=checkTypes