How to reduce an array objects based on an array of items

Question

How do I turn the following array of objects (packageMap) into a string of names based on an array of matching id's

I am imagining it to be a combination of filter and map but I can't understand it!

    const packageMap = [
    {
      id: `g3IbvxHPGt4xUVfYK`,
      name: `Package 1 - Cost £10`
    },
    {
      id: `HPGKCapDCJS76sgd7`,
      name: `Package 2 - Cost £20`
    },
    {
      id: `jbd73hndxJH6U6j6s`,
      name: `Package 3 - Cost £1`
    },
    {
      id: `5F53DSndxJH6nns22`,
      name: `Package 3 - Cost £5`
    }
  ];

  const matchingIDs = ['5F53DSndxJH6nns22', 'HPGKCapDCJS76sgd7'];

If I can somehow get an array of names from packageMap to look like this

let packages = ['Package 3 - Cost £5', 'Package 2 - Cost £20']

I can then use join on packages

let joined = packages.join(' and ')

let outStr = `You are subscribed to ${joined}`

console.log(outStr)

// "You are subscribed to Package 3 - Cost £5 and Package 2 - Cost £20"

I am using node so not constrained by old browsers or anything like that, so latest versions of answers are fine.

Xesenix · Accepted Answer · 2020-06-12 10:21:14Z

4

packageMap.filter(({ id }) => matchingIDs.includes(id)).map(({ name }) => name)

answered Jun 12, 2020 at 10:21

Xesenix

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Comments

djcaesar9114 · Accepted Answer · 2020-06-12 10:19:29Z

2

This would work:

const packageMap = [
  {
    id: `g3IbvxHPGt4xUVfYK`,
    name: `Package 1 - Cost £10`
  },
  {
    id: `HPGKCapDCJS76sgd7`,
    name: `Package 2 - Cost £20`
  },
  {
    id: `jbd73hndxJH6U6j6s`,
    name: `Package 3 - Cost £1`
  },
  {
    id: `5F53DSndxJH6nns22`,
    name: `Package 3 - Cost £5`
  }
];

const matchingIDs = ['5F53DSndxJH6nns22', 'HPGKCapDCJS76sgd7'];

let packages = matchingIDs.map(x => packageMap.find(y => y.id == x).name)

console.log(packages)

answered Jun 12, 2020 at 10:19

djcaesar9114

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Comments

Siva Kondapi Venkata · Accepted Answer · 2020-06-12 16:30:45Z

1

Use reduce and includes

const packageMap = [
  {
    id: `g3IbvxHPGt4xUVfYK`,
    name: `Package 1 - Cost £10`,
  },
  {
    id: `HPGKCapDCJS76sgd7`,
    name: `Package 2 - Cost £20`,
  },
  {
    id: `jbd73hndxJH6U6j6s`,
    name: `Package 3 - Cost £1`,
  },
  {
    id: `5F53DSndxJH6nns22`,
    name: `Package 3 - Cost £5`,
  },
];

const matchingIDs = ["5F53DSndxJH6nns22", "HPGKCapDCJS76sgd7"];

const names = packageMap.reduce(
  (acc, { id, name }) => (matchingIDs.includes(id) ? [...acc, name] : acc),
  []
);

console.log(names);

answered Jun 12, 2020 at 16:30

Siva Kondapi Venkata

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