[英]Iterate over object with some keys and array of objects inside
Assuming I have this data format:假设我有这种数据格式:
const matchedProperty = "property1"
const jsonObject = {
"property1": {
param1: '',
param2: '',
param3: '',
data: [
{key: value},
{key: value},
{key: value},
{key: value}
],
param4: ''
},
"propery2": {
param1: '',
param2: '',
param3: '',
data: [
{key: value},
{key: value},
{key: value},
{key: value}
],
param4: ''
}
}
How can I check if the property exists inside this json and after that how can I extract only data[{}] and param1 for example?如何检查此 json 中是否存在该属性,然后如何仅提取 data[{}] 和 param1?
Can't think of something that would be helpful and working想不出有用且有效的东西
Title doesn't match with body, so here's iteration and direct access:标题与正文不匹配,所以这里是迭代和直接访问:
let object = { a: 1, b: 2, c: 3 }
for (let key in object) {
console.log(key + ' = ' + object[key])
}
// a = 1
// b = 2
// c = 3
let vector = ['a', 'b', 'c']
for (let element of vector) {
console.log(element)
}
// a
// b
// c
let vector = ['a', 'b', 'c']
console.log(vector[0]) // a
console.log(vector[1]) // b
console.log(vector[2]) // c
console.log(vector[3]) // undefined
let object = { a: 1, b: 2, c: 3 }
console.log(object["a"]) // 1
console.log(object.a) // 1
console.log(object["b"]) // 2
console.log(object.b) // 2
console.log(object["c"]) // 3
console.log(object.c) // 3
console.log(object["d"]) // undefined
console.log(object.d) // undefined
Since undefined
won't trigger on an if-condition but values will, just write if object["key"]
;由于
undefined
不会在 if 条件下触发,但值会触发,只需编写if object["key"]
; it will execute the next code block if the key exists, otherwise it won't.如果密钥存在,它将执行下一个代码块,否则不会。 (Not suggested practice.)
(不建议练习。)
something like this?像这样的东西?
const matchedProperty = "property1" const jsonObject = { "property1": { param1: '', param2: '', param3: '', data: [ {key: 'value'}, {key: 'value'}, {key: 'value'}, {key: 'value'} ], param4: '' }, "propery2": { param1: '', param2: '', param3: '', data: [ {key: 'value'}, {key: 'value'}, {key: 'value'}, {key: 'value'} ], param4: '' } } const result = jsonObject.hasOwnProperty(matchedProperty)?{param1: jsonObject[matchedProperty].param1, data: jsonObject[matchedProperty].data}:{} console.log(result)
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