Is it possible to create complex objects at runtime in javascript ? If so, what is the correct syntax ?
var food = {};
food["fruit"]["yellow"] = "banana";
food["meat"]["red"] = "steak";
food."fruit"."green" = "apple";
2 Answers
It's not clear what you're trying to do. If you want to build that object up all at once, then you could do something like:
var food = {
fruit: {
yellow: 'banana',
green: 'apple'
},
meat: {
red: 'steak'
}
};
If you need to piece it together one nested object at a time, then you just need to make sure that you are creating a new object to add properties to.
For example, your line:
food["fruit"]["yellow"] = "banana";
will probably fail because food.fruit does not exist.
You should do:
var food = {};
food.fruit = {};
food.fruit.yellow = 'banana';
1 Comment
Agnaroc
I'm iterating through data in a file.I don't know if food is going to come along at all. So if there isn't any way around it I'll always use if(data.fruit == undefined) {var fruit = {}; } //Do something with data.fruit
You could write a function to add data to your object. e.g.
function addEntry(obj, entry) {
if(entry.length < 2) return;
if(entry.length === 2) obj[entry[0]] = entry[1];
else {
if(!obj[entry[0]] || typeof obj[entry[0]] !== "object") obj[entry[0]] = {};
addEntry(obj[entry[0]], entry.slice(1));
}
}
var data = [
["fruit", "yellow", "banana"],
["meat", "red", "steak"],
["fruit", "green", "apple"]
];
var obj = {};
for(var i = 0; i < data.length; i++) {
addEntry(obj, data[i]);
}
console.log(obj);
var food = {}; food["fruit"] = {}; food["fruit"]["yellow"] = "banana"; food["meat"] = {}; food["meat"]["red"] = "steak"; food["fruit"]["green"] = "apple";