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0

137
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JS get all the arrays within an array

I have an object that looks like the following:

const test = {
  leagues: [
    {
      timezone: "GMT",
      date: "1/2/2",
      premierLeague: [
        { name: "Liverpool", age: 1892 },
        { name: "Manchester Utd", age: 1878 }
      ],
      laLiga: [
        {
          team: "Real Madrid",
          stadium: "Bernabeu"
        },
        {
          team: "Barcelona",
          stadium: "Camp Nou"
        }
      ]
    }
  ]
};

and I want the result to look like

const result = [
  { name: "Liverpool", age: 1892 },
  { name: "Manchester Utd", age: 1878 },
  {
    team: "Real Madrid",
    stadium: "Bernabeu"
  },
  {
    team: "Barcelona",
    stadium: "Camp Nou"
  }
];

I have tried to use flat() but am having trouble getting the arrays within the leagues. The result will be dynamic so I need to be able to get all the arrays within leagues. Can anyone point me in the correct direction to do this?

about 4 years ago · Juan Pablo Isaza
3 answers
Answer question

0

If your object structure doesn't go an deeper than that, this long one-liner should work:

const result = test.leagues.reduce((arr, obj) => Object.values(val).reduce((innerArr, val) => Array.isArray(val) ? innerArr.concat(val) : innerArr, arr), []);

Somewhat ungolfed:

const result = test.leagues.reduce((arr, obj) => {
  return Object.values(val).reduce((innerArr, val) => {
    return Array.isArray(val)
      ? innerArr.concat(val) 
      : innerArr
  }, arr);
}), []);
about 4 years ago · Juan Pablo Isaza Report

0

You might be looking for

const result = test.leagues.flatMap(league =>
  Object.values(league).filter(Array.isArray).flat()
);
about 4 years ago · Juan Pablo Isaza Report

0

This sounds weird, you'll end up with objects of different shapes in the same array. I'm not sure how you'll deal with that.

It looks like you're trying to concatenate every value of test.leagues that is itself an array.

const test = {
  leagues: [{
    timezone: "GMT",
    date: "1/2/2",
    premierLeague: [{
        name: "Liverpool",
        age: 1892
      },
      {
        name: "Manchester Utd",
        age: 1878
      }
    ],
    laLiga: [{
        team: "Real Madrid",
        stadium: "Bernabeu"
      },
      {
        team: "Barcelona",
        stadium: "Camp Nou"
      }
    ]
  }]
};


const output = [];
for (const league of test.leagues) {
  for (const key in league) {
    if (Array.isArray(league[key])) {
      // Push each element in `league[key]` onto `output`
      // so we don't have to flatten it later
      output.push(...league[key]);
    }
  }
}
console.log({
  output
});

about 4 years ago · Juan Pablo Isaza Report
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