Given this simple example:
const testdata = [
{
id: "001",
name: "Bob",
comments: [
{
id: "01",
text: "Hello World"
},
{
id: "02",
text: "Hello Mars"
}
]
}
];
I would like to output all the comments for this object:
With this I get the id and the name
testdata.map(i => { console.log(i.id + i.name)});
What is the best way to output the nested array that holds the comments?
Get an array of comments arrays with Array.map(), then flatten by spreading into Array.concat():
const testdata = [{"id":"001","name":"Bob","comments":[{"id":"01","text":"Hello World"},{"id":"02","text":"Hello Mars"}]},{"id":"002","name":"Sara","comments":[{"id":"03","text":"Hello Jupiter"},{"id":"04","text":"Hello Moon"}]}];
const comments = [].concat(...testdata.map((d) => d.comments));
console.log(comments);You can use array#reduce with array#forEach.
const testdata = [ { id: "001", name: "Bob", comments: [ { id: "01", text: "Hello World" }, { id: "02", text: "Hello Mars" } ] } ],
result = testdata.reduce((r, {comments}) => {
comments.forEach(o => r.push({...o}));
return r;
},[]);
console.log(result);
testdata.reduce((acc, {comments}) => acc.concat(...comments), []) also.This will do the trick:
testdata.map(i => i.comments.map(comment => console.log(comment)));
If you just want to display comments then using forEach you can achieve this(forEach not create extra variable)
const testdata = [{"id":"001","name":"Bob","comments":[{"id":"01","text":"Hello World"},{"id":"02","text":"Hello Mars"}]},{"id":"002","name":"Sara","comments":[{"id":"03","text":"Hello Jupiter"},{"id":"04","text":"Hello Moon"}]}];
testdata.forEach(x => x.comments.forEach(y => console.log(y)));