Why is my map() with spread syntax not working?
Why is my map() with spread syntax not working?
I'm really not seeing where this is going wrong. I've seen posts of this particular example from O'Reilly's Learning React, by Banks & Porcello. However, the posts seem to work fine, but my example does not. If I have a typo, I don't see it. Where's my flaw? I don't know why I get a null string value instead of "HB Woodlawn"
<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<meta name="viewport"
content="width=device-width, user-scalable=no, initial-scale=1.0, maximum-scale=1.0, minimum-scale=1.0">
<meta http-equiv="X-UA-Compatible" content="ie=edge">
<title></title>
<script src="https://unpkg.com/babel-standalone@6.15.0/babel.min.js"></script>
</head>
<body>
<script type="text/babel">
// Editing one object in an array of objects
let schools = [
name: 'Yorktown',
name: 'Stratford',
name: 'Washington & Lee',
name: 'Wakefield'
];
const editName = (oldName, newName, arr) =>
arr.map(item =>
if (item.name === oldName)
return
...item,
name
else
return item
);
let updatedSchools = editName('Stratford', 'HB Woodlawn', schools);
console.log(updatedSchools[1]); // name: ""
console.log(schools[1]); // name: "Stratford"
</script>
</body>
</html>
...
ummm,
... is spread operator right?– illiteratewriter
Dec 18 '17 at 9:57
...
1 Answer
1
let schools = [
name: 'Yorktown',
name: 'Stratford',
name: 'Washington & Lee',
name: 'Wakefield'
];
const editName = (oldName, newName, arr) =>
arr.map(item =>
if (item.name === oldName)
return
...item,
name: newName
else
return item
);
let updatedSchools = editName('Stratford', 'HB Woodlawn', schools);
console.log(updatedSchools[1]); // name: ""
console.log(schools[1]); // name: "Stratford"
You hadn't added the new value for the name, instead had left it empty. Added name:newName
name:newName
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– illiteratewriter
Dec 18 '17 at 11:21
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Note:
...is not an operator. (And before anyone says it: Ignore the URL on the MDN page, it was an error by the person who created the page.)– T.J. Crowder
Dec 18 '17 at 9:52