const {ccclass, property} = cc._decorator;

@ccclass export default class NewClass extends cc.Component {

// LIFE-CYCLE CALLBACKS:

objectFromResource: Object

onLoad () {
    console.log("Starting onLoad() Function")
    var url = cc.url.raw('resources/json_resource.json')
    cc.loader.load(url, (err, res) => {
        cc.log(res)
        this.objectFromResource = res
        console.log("Loaded URL")
    });
    console.log("Ending onLoad() Function")
}

start () {
    console.log('Starting start() Function')
    console.log(this.objectFromResource) //logging as null
    console.log('Ending start() function')
}

update (dt) {

}
}

Cocos Creator v2.1.1
JSONReader.ts:16 Starting onLoad() Function
JSONReader.ts:33 Ending onLoad() Function
JSONReader.ts:37 Starting start() Function
JSONReader.ts:38 undefined
JSONReader.ts:39 Ending start() function
JSONReader.ts:22 {__type__: "cc.JsonAsset", _name: "json_resource", _objFlags: 0, _native: "", json: Array(784)}
JSONReader.ts:24 Loaded URL