如何以自定义方式读取 JSON 文件

Question

I have a JSON object like below

{
 "db": {
 "name": "db",
 "connector": "memory"
  },
"MySql": {
   "host": "localhost",
   "port": 3306,
   "database": "users",
   "username": "root",
   "password": "",
   "name": "MySql",
   "connector": "mysql"
  },
"postgreDS": {
   "host": "localhost", 
   "port": 1234,
   "database": "abc", 
   "username": "postgres", 
   "password": "abc",
   "name": "postgreDS",
   "connector": "postgresql"
 }

I need the following output from this object.

{"db", "MySql", "postgreDS"}

how should I extract the above information from whole JSON object in JavaScript. and how I will read the sub keys and there values.

Answer 1

Something like this (where obj is your JSON-object):

var objectProperties = [];
for(var prop in obj){
    objectProperties.push(prop);
}
console.log(JSON.stringify(objectProperties)); // ["db", "MySql", "postgreDS"]

Answer 2

If you're merely looking to get the keys of the nested objects use Object.keys :

var keys = Object.keys(obj); // [ "db", "MySql", "postgreDS" ]

If you're looking to get the values from within the nested objects based on a specified key here's a generic function that will return an array of values:

function getValueFromKey(obj, key) {
    return Object.keys(obj).map(function (el) {
        return obj[el][key];
    });
}

getValueFromKey(obj, 'name'); // [ "db", "MySql", "postgreDS" ]
getValueFromKey(obj, 'connector'); // [ "memory", "mysql", "postgresql" ]

DEMO

Answer 3

Try the FIDDLE ,

javascript

$(function(){
var output = {};
var items = {
 "db": {
 "name": "db",
 "connector": "memory"
  },
"MySql": {
   "host": "localhost",
   "port": 3306,
   "database": "users",
   "username": "root",
   "password": "",
   "name": "MySql",
   "connector": "mysql"
  },
"postgreDS": {
   "host": "localhost", 
   "port": 1234,
   "database": "abc", 
   "username": "postgres", 
   "password": "abc",
   "name": "postgreDS",
   "connector": "postgresql"
 }};

for(var propertyName in items) {
    output.push(propertyName); // output will have the required output

}
console.log(output);
});