如何深层过滤对象(不是对象数组) [英] How to deep filter objects (not object arrays)

问题描述

我正在使用看起来像这样的JS数据结构:

I'm working with a JS data structure that looks something like this:

table = {
  row1: {
    col1: 'A',
    col2: 'B',
    col3: 'C'
  },
  row2: {
    col1: 'D',
    col2: 'A',
    col3: 'F'
  },
  row3: {
    col1: 'E',
    col2: 'G',
    col3: 'C'
  }
};

你们将如何使用JavaScript的本机filter/map/reduce函数过滤该对象，以生成包含属性col3 ="C"的行对象键的数组?

How would you guys filter this object using JavaScript's native filter/map/reduce functions to produce an array of row object keys that contain the property col3 = "C"?

在这种情况下，它将返回['row1', 'row3'].

In this case, it would return ['row1', 'row3'].

这是我最初基于另一个答案:

Object.keys(Object.keys(table).reduce(function(accumulator, currentValue) {
  if (table[currentValue].col3==='C') accumulator[currentValue] = table[currentValue];
  return accumulator;
}, {}));

但是，我已经接受了使用filter()的以下解决方案，因为它效率更高.可接受的答案使用ES6语法，但是ES5语法由@Paulpro提供:

However, I have accepted the solution below using filter() because it's more efficient. The accepted answer is in ES6 syntax, but ES5 syntax was provided by @Paulpro:

Object.keys(table).filter(function(row) {
  return table[row].col3==='C';
});

(请注意，这里有类似的解决方案，但它们使用自定义功能，并且不如所提供的可接受的答案那么简洁下方.)

(Note that there are similar solutions out there, but they use custom functions and are not as concise as the accepted answer provided below.)

推荐答案

您可以使用Object.keys，然后使用原始对象进行过滤:

You could use Object.keys and then filter using the original object:

table = {
  row1: {
    col1: 'A',
    col2: 'B',
    col3: 'C'
  },
  row2: {
    col1: 'D',
    col2: 'A',
    col3: 'F'
  },
  row3: {
    col1: 'E',
    col2: 'G',
    col3: 'C'
  }
};

console.log(Object.keys(table).filter(function(t) { return table[t].col3 === 'C'}))

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