I have an array that repeats itself. I'm looking for a way to omit the duplicate values i.e.

[['cream'], ['cake'], ['cheese'], ['bread'], ['cream'], ['cake'], ['cheese'], ['bread'], ['butter']]

becomes

[['cream'], ['cake'], ['cheese'], ['bread'], ['butter']]

any clean way to do this?

CodePudding user response：

console.log(Object.keys([
  ['cream'],
  ['cake'],
  ['cheese'],
  ['bread'],
  ['cream'],
  ['cake'],
  ['cheese'],
  ['bread'],
  ['butter']
].reduce((acc, val) => { // map to object
  acc[val] = true
  return acc;
}, {})).map(key => [key])) // map object back to array

CodePudding user response：

• Define a Set to store array elements
• Using Array#reduce, iterate over the list. In every iteration, convert the current array to a string by joining its elements using Array#join. Then, if the value is not already in the set, add it and push the current array to the accumulated list.

const arr = [['cream'], ['cake'], ['cheese'], ['bread'], ['cream'], ['cake'], ['cheese'], ['bread'], ['butter']];

const set = new Set();
const res = arr.reduce((list, e) => {
  const val = e.join();
  if(!set.has(val)) {
    set.add(val);
    list.push(e);
  }
  return list;
}, []);

console.log(res);

CodePudding user response：

One liner here:

const data = [['cream'], ['cake'], ['cheese'], ['bread'], ['cream'], ['cake'], ['cheese'], ['bread'], ['butter']];

console.log([...new Set(data.flat())].map(i => [i]))