v8.queryObjects(ctor[, options])

• ctor <Function> 该构造函数可用于在原型链上搜索，以便过滤堆中的目标对象。
• options <undefined> | <Object>
  • format <string> 如果是 'count'，则返回匹配对象的数量。如果是 'summary'，则返回包含匹配对象摘要字符串的数组。
• 返回值：{number|Array}

这类似于 Chromium DevTools 控制台提供的 queryObjects() 控制台 API。它可用于在完整垃圾回收后搜索在堆中具有匹配构造函数原型链的对象，这对于内存泄漏回归测试非常有用。为了避免意外结果，用户应避免在他们无法控制实现的构造函数上使用此 API，或在应用中可能被其他方调用的构造函数上使用此 API。

【This is similar to the queryObjects() console API provided by the Chromium DevTools console. It can be used to search for objects that have the matching constructor on its prototype chain in the heap after a full garbage collection, which can be useful for memory leak regression tests. To avoid surprising results, users should avoid using this API on constructors whose implementation they don't control, or on constructors that can be invoked by other parties in the application.】

为了避免意外泄露，此 API 不会返回找到的对象的原始引用。默认情况下，它会返回找到的对象数量。如果 options.format 为 'summary'，它会返回一个包含每个对象简要字符串表示的数组。此 API 提供的可见性类似于堆快照所提供的，而用户可以节省序列化和解析的开销，并在搜索过程中直接过滤目标对象。

【To avoid accidental leaks, this API does not return raw references to the objects found. By default, it returns the count of the objects found. If options.format is 'summary', it returns an array containing brief string representations for each object. The visibility provided in this API is similar to what the heap snapshot provides, while users can save the cost of serialization and parsing and directly filter the target objects during the search.】

只有在当前执行上下文中创建的对象才会包含在结果中。

【Only objects created in the current execution context are included in the results.】

const { queryObjects } = require('node:v8');
class A { foo = 'bar'; }
console.log(queryObjects(A)); // 0
const a = new A();
console.log(queryObjects(A)); // 1
// [ "A { foo: 'bar' }" ]
console.log(queryObjects(A, { format: 'summary' }));

class B extends A { bar = 'qux'; }
const b = new B();
console.log(queryObjects(B)); // 1
// [ "B { foo: 'bar', bar: 'qux' }" ]
console.log(queryObjects(B, { format: 'summary' }));

// Note that, when there are child classes inheriting from a constructor,
// the constructor also shows up in the prototype chain of the child
// classes's prototype, so the child classes's prototype would also be
// included in the result.
console.log(queryObjects(A));  // 3
// [ "B { foo: 'bar', bar: 'qux' }", 'A {}', "A { foo: 'bar' }" ]
console.log(queryObjects(A, { format: 'summary' }));import { queryObjects } from 'node:v8';
class A { foo = 'bar'; }
console.log(queryObjects(A)); // 0
const a = new A();
console.log(queryObjects(A)); // 1
// [ "A { foo: 'bar' }" ]
console.log(queryObjects(A, { format: 'summary' }));

class B extends A { bar = 'qux'; }
const b = new B();
console.log(queryObjects(B)); // 1
// [ "B { foo: 'bar', bar: 'qux' }" ]
console.log(queryObjects(B, { format: 'summary' }));

// Note that, when there are child classes inheriting from a constructor,
// the constructor also shows up in the prototype chain of the child
// classes's prototype, so the child classes's prototype would also be
// included in the result.
console.log(queryObjects(A));  // 3
// [ "B { foo: 'bar', bar: 'qux' }", 'A {}', "A { foo: 'bar' }" ]
console.log(queryObjects(A, { format: 'summary' }));拷贝