标签:undefined space == 缩进 null 类型 不同 return 对象
JSON.stringify() 语法
JSON.stringify(value[, replacer[, space]])
value 被序列化为字符串的对象
replacer 根据类型不同,其行为也不一样。如果是一个函数类型,则相当于是一个filter,可以对序列化的键值对进行加工处理;如果是一个数组,则只有符合数组中名称的key才会被输出
space 如果为0或不填,则不进行格式化处理;如果为大于0的数值,则表示每级缩进空格数;如果是一个字符串,则表示每级缩进时替代空格进行填充的字符串内容。
通过以下的data作为示例:
let data = {
name: ‘wang‘,
age: 28,
address: null,
favorites: undefined,
company: {
name: ‘world village‘,
address: ‘Beijing city‘
}
}
不加任何参数,直接输出:
console.log(JSON.stringify(data))
结果为:
{"name":"wang","age":28,"address":null,"company":{"name":"world village","address":"Beijing city"}}
第二个参数为数组:
console.log(JSON.stringify(data, [‘name‘, ‘age‘]))
结果为:
{"name":"wang","age":28}
第二个参数是一个函数:
console.log(
JSON.stringify(data, (k, v) => {
if (‘age‘ == k) {
return undefined
}
return v
})
)
结果为:
{"name":"wang","address":null,"company":{"name":"world village","address":"Beijing city"}}
如果第三个参数为0或者null:
console.log(JSON.stringify(data, null, 0))
则结果为:
{"name":"wang","age":28,"address":null,"company":{"name":"world village","address":"Beijing city"}}
如果第三个参数为大于0的数值:
console.log(JSON.stringify(data, null, 2))
则结果为:
{
"name": "wang",
"age": 28,
"address": null,
"company": {
"name": "world village",
"address": "Beijing city"
}
}
如果第三个参数为字符串:
console.log(JSON.stringify(data, null, ‘**‘))
则结果为:
{
**"name": "wang",
**"age": 28,
**"address": null,
**"company": {
****"name": "world village",
****"address": "Beijing city"
**}
}
如果过滤值为null或者undefined的键值对?
let data = {
name: ‘wang‘,
age: 28,
address: null,
favorites: undefined,
men: true,
women: false,
company: {
name: ‘world village‘,
address: ‘Beijing city‘
}
}
console.log(
JSON.stringify(data, (k, v) => {
if (null != v && undefined != v) return v
})
)
标签:undefined space == 缩进 null 类型 不同 return 对象
原文地址:https://www.cnblogs.com/popgis/p/11756624.html