javascript - 如何通过搜索文本返回 JSON 数组中项目的索引位置？

Question

这是我的 JSON 数组:

var planets = [{
  "Name": "Mercury",
  "Temperature": "427°C",
  "Position" : 1
}, {
  "Name": "Venus",
  "Temperature": "462°C",
  "Position" : 2

}, {
  "Name": "Earth",
  "Temperature": "16°C",
  "Position" : 3
}]

使用文本“Earth”是否有一种方法可以返回项目 Earth 在我的 Planets 数组中的索引位置？

例如:

planets.find("Earth")

Answer 1

普通 JS:findIndex

The findIndex() method returns an index in the array, if an element in the array satisfies the provided testing function. Otherwise -1 is returned.

[{
  "Name": "Mercury",
  "Temperature": "427°C",
  "Position" : 1
}, {
  "Name": "Venus",
  "Temperature": "462°C",
  "Position" : 2

}, {
  "Name": "Earth",
  "Temperature": "16°C",
  "Position" : 3
}].findIndex(x => x.Name === "Earth")

如果您使用的是 IE 9+，则可以使用 reduce function

The reduce() method applies a function against an accumulator and each value of the array (from left-to-right) to reduce it to a single value.

[{
  "Name": "Mercury",
  "Temperature": "427°C",
  "Position" : 1
}, {
  "Name": "Venus",
  "Temperature": "462°C",
  "Position" : 2

}, {
  "Name": "Earth",
  "Temperature": "16°C",
  "Position" : 3
}].reduce(function (foundSoFar, x, i) { // Note no arrow funcion
  if (foundSoFar < 0 && x.Name === "Earth") {
    return i;
  } else {
    return foundSoFar;
  }
}, -1);

或者，使用库的实现，如 ramda