javascript - 如何在无限循环中重用数组函数

Question

真正的代码比较大，就不贴了。它看起来很像这样:

class A {
    process(source) {
        // I perform several operations with array helper functions here:
        const filtered = source.filter(item => item);
        const condition = filtered.some(item => item);

        if (condition) {
            const mapped = source.map(item => /* Mapping operations... */);
            const sorted = mapped.sort((a, b) => { /* Some sort conditions... */ });
            return sorted;
        } else {
            const mapped2 = filtered.map(item => /* A different mapping operation... */);
            return mapped2;
        }
    }
}

const a = new A();

while (true) {
    const source = getSourceFromSomewhere(); // Array (40 - 50 items aprox)
    const b = a.process(source);
    // ...
}

The problem: Basically, performance; "Don't make functions within a loop".

在每次迭代中都会创建一堆匿名函数。

我的解决方案:

class A {
    // Predefine it:
    sort() { /* Sort logic */ }
    map() { /* Map logic */ }
    map2() { /* Map logic */ }
    filter() { /* Filter logic */ }
    some() { /* Condition */ }

    process(source) {
        const filtered = source.filter(this.filter); // Note: Scope of 'this' is changed.
        const condition = filtered.some(this.some);

        if (condition) {
            const mapped = source.map(this.map);
            const sorted = mapped.sort(this.sort);
            return sorted;
        } else {
            const mapped2 = filtered.map(this.map2);
            return mapped2;
        }
    }
}

Another problem: Some of this functions need access to properties of the object itself, but the scope of this has been changed.

值得调用 .bind(this) 而不是创建匿名函数吗？还是几乎一样？

如果是我，你会怎么做？

提前致谢。

Answer 1

要在类中初始化绑定(bind)函数，您可以这样做

class Test {
    fn = (t) => this[t]
}

基本上与您想做的一样。