如何在 react/javascript 中通过首字母过滤对象数组

Question

I am fairly new to React and javascript environment so some of the syntax and errors don't make sense to me. I have tried using the filter function something like this but gives me an error of undefined is not an object.

const temp = example.filter(x => x.includes('A'))

Example:

data = [{id: 1, type: Pizza}, {id: 2, type: Taco}, {id: 3, type: Pasta}, {id: 4, type: Sandwich}, {id: 5, type: Pumpkin Pie}]

Output:

temp = [{id: 1, type: Pizza}, {id: 3, type: Pasta}, {id: 5, type: Pumpkin Pie}]

Answer 1

Try to use startWith :

 let data = [{id: 1, type: 'Pizza'}, {id: 2, type: 'Taco'}, {id: 3, type: 'Pasta'}, {id: 4, type: 'Sandwich'}, {id: 5, type: 'Pumpkin Pie'}] // Output: let result = data.filter(f => f.type.toLowerCase().startsWith('p')) console.log(result)

Answer 2

The reason your code does not work is because you are not accessing the properties right and trying to match a whole object. x.includes('A') is doing a comparison with the whole object that is x .

If you just want to filter the objects in an array based on some specific property in them here's how you can do it.

Sample:

let data = [{id: 1, type: "Pizza"}, {id: 1, type: "Taco"}, {id: 1, type: "Pasta"}, {id: 1, type: "Sandwich"}, {id: 1, type: "Pumpkin Pie"}]

Process:

data.filter(x => x.type.toLowerCase().includes('pizza'))

Output:

[{id: 1, type: Pizza}]

or in your case if you want to just sort by the first letter, you can do:

data.filter(x => x.type.toLowerCase().startsWith('p'))

Returns: [ {id: 1, type: "Pizza"},{id: 1, type: "Pasta"}, {id: 1, type: "Pumpkin Pie"} ]`