Greetings everyone, I have a question regarding performance implications in JavaScript. I have a JSON query result as follows:
[{'name': 'a'}, {'name': 'b'}]
For another query, I need to manipulate it to the following format:
['a', 'b']
What would be the most efficient method to achieve this? Would it be through native JSON libraries or simple JSON/string parsing?
Thank you in advance
When utilizing the forEach method:
var array1 = [{"name": "a"}, {"name": "b"}];
var array2 = [];
array1.forEach(function (value) {
array2.push(value.name);
});
console.log(array2); // Displays ["a", "b"]
Alternatively, using the map method:
var array1 = [{"name": "a"}, {"name": "b"}];
var array2 = array1.map(function(v) {
return v.name;
});
console.log(array2); // Displays ["a", "b"]
Here's a simple solution you might consider:
Just iterate through the JSON array and extract each name value into a new array.
var data = [{name: 'x'}, {name: 'y'}];
var output = [];
var length = data.length;
for(var j = 0; j < length; j++){
output.push(data[j].name);
}
console.log(output);
Based on the performance tests I've seen, it seems like using map would be the best option as it often outperforms the native for-loop, especially depending on the browser. It appears that libraries like underscore and lodash don't perform as well compared to the native for-loop and map.
If you're working with a JavaScript object rather than a JSON string:
var arr = [{name: 'a'}, {name: 'b'}];
var out = arr.map(function (el) {
return el.name;
});
If you have a JSON string but mistakenly worded your question:
var json = '[{"name":"a"},{"name":"b"}]';
var out = JSON.parse(json).map(function (el) {
return el.name;
});
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