Getting a string from JSON object with args from another object - node.js

Question

Say I have a JSON file like this:
{"ABCD":{
"1_99":{"type": 3, "serverPath": "http://some.website.com"}
},
"EFGH":{
"1_00":{"type": 2, "serverPath": "http://another.meme.website/"}
"1_01":{"type": 2, "serverPath": "http://yet.another.website.com/memes"}
},
etc..
}
and I want to reference one of the element in that file:
let appList = require('./config/appList.json');
...
var uri = appList.ABCD.1_99.serverPath;
where element name "ABCD" and "1_99" comes from another object and it's not always the same, say:
var uri = appList. [httpPOSTRequest.app_id] . [httpPOSTRequest.app_ver] . serverPath;
which I wonder if there's any way that can do so please.

Answer 1

You can loop through your appList or you can use other libraries like (https://lodash.com/). I have implemented it with simple loop
let appList = {
"ABCD": {
"1_99": {
"type": 3,
"serverPath": "http://some.website.com"
}
},
"EFGH": {
"1_00": {
"type": 2,
"serverPath": "http://another.meme.website/"
}
}
}
Object.keys(appList).map((d,i)=>{
Object.keys(appList[d]).map((data, index)=>{
console.log(`server path ${i} : ${appList[d][data].serverPath}`);
})
})

Answer 2

You can encapsulate your search properties in a search object, then use this to access your appList object using JavaScript bracket notation.
I've wrapped this up in a getServerPath function which also conveys the intent of the exercise.
We'll return null if we can't find the path in question.
Also, bear in mind, there is a very useful function in the lodash library _.get which can do an awful lot of this stuff for you, I've included an example below.
I hope this helps you!
// Get the required server path given the searchInput object
function getServerPath(appList, searchInput) {
if (!searchInput) return null;
if (!appList[searchInput.property1]) return null;
if (!appList[searchInput.property1][searchInput.property2]) return null;
return appList[searchInput.property1][searchInput.property2].serverPath;
}
// In Node.js we would use require('file.json') to define this.
let appList = {
"ABCD": {
"1_99": {
"type": 3,
"serverPath": "http://some.website.com"
}
},
"EFGH": {
"1_00": {
"type": 2,
"serverPath": "http://another.meme.website/"
}
}
}
// Search object input
let searchInput1 = { property1: "ABCD", property2: "1_99" };
let searchInput2 = { property1: "EFGH", property2: "1_00" };
let searchInput3 = { property1: "DOESNTEXIST", property2: "1_00" };
console.log("Server path 1:", getServerPath(appList, searchInput1));
console.log("Server path 2:", getServerPath(appList, searchInput2));
console.log("Server path 3:", getServerPath(appList, searchInput3));
// Using the very useful lodash _.get
console.log("Server path (using lodash _.get):", _.get(appList, "ABCD.1_99.serverPath"));
<script src="https://cdnjs.cloudflare.com/ajax/libs/lodash.js/4.17.15/lodash.js"></script>