How can I output multiple results from an array

Question

I have this array of objects, that initially only had name and unit fields. I recently added a unitConv field of array type.

I used to output an array of strings with the name and unit from every object.

const ingredients = [
  {name: 'wine', unit: 'ml', unitConv: []},
  {name: 'salt', unit: 'gr', unitConv: [{unitMeasure: { name: 'spoon'}}, {unitMeasure: { name: 'tea-spoon'}}]},
  {name: 'onion', unit: 'piece', unitConv: []},
]

const response = ingredients.map(ing => `${ing.name} [${ing.unit}]`)

And this is the response:

["wine [ml]", "salt [gr]", "onion [piece]"]

Now that I added unitConv, I want to see if any unitConv are available in the object, and pass those too, as options, like this:

["wine [ml]", "salt [gr]", "onion [piece]", "salt[spoon]", "salt[tea-spoon]"]

And I want to keep the initial value of salt too, the one the uses the 'gr' as a unit. So for salt, because I have one unit and two unitConv, I want to output it three times, with each of this options. If one of the objects doesn't have unitConv, the unitConv fields will appear as an empty array, like in the example above.

Does my answer work for you?

Unmitigated
– Unmitigated

2020-11-30 01:09:09 +00:00
Commented Nov 30, 2020 at 1:09 — Unmitigated
– Unmitigated, Commented Nov 30, 2020 at 1:09
Yes it does, thank you!

allneonlokes
– allneonlokes

2020-12-01 09:01:41 +00:00
Commented Dec 1, 2020 at 9:01 — allneonlokes
– allneonlokes, Commented Dec 1, 2020 at 9:01

Unmitigated · Accepted Answer · 2020-11-27 14:16:18Z

5

You can use Array#flatMap to create the second array to concatenate with the first.

const ingredients = [
  {name: 'wine', unit: 'ml', unitConv: []},
  {name: 'salt', unit: 'gr', unitConv: [{unitMeasure: { name: 'spoon'}}, {unitMeasure: { name: 'tea-spoon'}}]},
  {name: 'onion', unit: 'piece', unitConv: []},
]

const response = ingredients.map(ing => `${ing.name} [${ing.unit}]`)
     .concat(ingredients.flatMap(({name, unitConv})=>
         unitConv.map(x => `${name} [${x.unitMeasure.name}]`)));
console.log(response);

answered Nov 27, 2020 at 14:16

Unmitigated

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Comments

Mister Jojo · Accepted Answer · 2020-11-27 14:32:28Z

0

a simple array reduce method:

const ingredients = 
        [ { name: 'wine', unit: 'ml', unitConv: [] } 
        , { name: 'salt', unit: 'gr', unitConv: 
              [ { unitMeasure: { name: 'spoon'     } } 
              , { unitMeasure: { name: 'tea-spoon' } } 
              ] 
          } 
        , { name: 'onion', unit: 'piece', unitConv: [] } 
        ] 

const resp2 = ingredients.reduce((resp,{name,unit,unitConv}) =>
        {
        resp.push( `${name} [${unit}]` )
        unitConv.forEach(({unitMeasure}) =>
          resp.push(`${name} [${unitMeasure.name}]`))
        return resp
        },[])

console.log( resp2 )

.as-console-wrapper{max-height:100% !important;top: 0;}

edited Nov 27, 2020 at 14:32

answered Nov 27, 2020 at 14:27

Mister Jojo

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Comments

hamid niakan · Accepted Answer · 2020-11-27 14:41:10Z

you can use flatMap and inside its callback function check for unitConv array lentgh, if it's true then you can use a map for that. here is the demo:

const ingredients = [{
    name: 'wine',
    unit: 'ml',
    unitConv: []
  },
  {
    name: 'salt',
    unit: 'gr',
    unitConv: [{
      unitMeasure: {
        name: 'spoon'
      }
    }, {
      unitMeasure: {
        name: 'tea-spoon'
      }
    }]
  },
  {
    name: 'onion',
    unit: 'piece',
    unitConv: []
  },
]

function strFormat(name, unit) {
  return `${name} [${unit}]`;
}

const result = ingredients.flatMap((ing) => {
  if (ing.unitConv.length) {
    const ingAllUnits = ing.unitConv.map((unit) => strFormat(ing.name, unit.unitMeasure.name));
    ingAllUnits.push(strFormat(ing.name, ing.unit));
    return ingAllUnits;
  } else return strFormat(ing.name, ing.unit);
});

console.log(result);

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