I have a JavaScript function that outputs all values from a JSON file to a Terminal, but when attempting to print a single value, I get the following error: Line 74 - Cannot read properties of undefined (reading 'width')
Here is the code:
var json = `{
"columns": [{
"fname": "John",
"lname": "Doe",
"age": "23"
},
{
"fname": "Jane",
"lname": "Doe",
"age": ""
},
{
"fname": "Tom",
"lname": "Johns",
"age": ""
},
{
"fname": "Brian",
"lname": "Wicks",
"age": "27"
},
{
"fname": "Tim",
"lname": "Stone",
"age": ""
},
{
"fname": "Fred",
"lname": "Wilson",
"age": ""
},
{
"fname": "Jason",
"lname": "Voorhees",
"age": "90"
}
],
"rows": [{
"data": {
"width": "2",
"height": "7",
"length": "",
"finalresult": "44",
"firstresult": "",
"secondresult": "300.00",
"thirdresult": "700.40"
}
}]
}`;
var obj = JSON.parse(json);
function printValues(obj) {
for(var k in obj) {
if(obj[k] instanceof Object) {
printValues(obj[k]);
} else {
console.log(obj[k] + "\n");
};
}
};
// Printing all the values from the resulting object
printValues(obj);
//print single value
//console.log(obj["columns"]["rows"]["data"]["width"] + "\n");
console.log("Print Indiviual values:");
console.log(obj["rows"]["data"]["width"] + "\n"); //The Error
...Could I get some assistance as to what I'm doing wrong? ...Thanks
As @Yarin and @codemonkey pointed out—you're trying to access the data object as a direct object property of rows, e.g. obj.rows.data which is wrong and will return undefined because data is not a property of the rows object. Instead it's the first (and only) entry in the array of objects that is rows.
You need to either change the syntax to:
obj.rows[0].data.width
Or take the data object out of the array and remove the array so that the rows object is structured like this:
const obj = {
rows: {
data: {
width: 1
}
}
}
// Then you can use this syntax...
console.log( obj.rows.data.width )
// or even this syntax if you want to...
console.log( obj['rows']['data']['width'] )I see that the width is the property of object data that is inside array rows...