10 examples of 'javascript reduce array of objects' in JavaScript

58
function reduceObjects() {
59
	var objs = Array.prototype.slice.call(arguments);
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	var acc = {}, obj;
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	while (objs.length) {
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		obj = objs.shift();
63
		if (!obj) { continue; }
64
		for (var k in obj) {
65
			if (typeof obj[k] == 'undefined' || obj[k] === null) { continue; }
66
			if (typeof obj[k] == 'object' && !Array.isArray(obj[k])) {
67
				acc[k] = reduceObjects(acc[k], obj[k]);
68
			} else {
69
				acc[k] = obj[k];
70
			}
71
		}
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	}
73
	return acc;
74
}

18
export function reduceObject(object, fn, result = {}) {
19
  eachProperty(object, function(name, value) {
20
    result = fn(result, name, value);
21
  });
22
  return result;
23
}

67
function reduce(array, reducer, index) {
68
  return array.reduce(function(prev, current) {
69
    return reducer(prev, current[index]);
70
  }, array[0][index]);
71
}

371
export function reduce(obj, func, value) {
372
  for (const i in obj) {
373
    value = func(value, obj[i], i);
374
  }
375
  return value;
376
}

58
export async function reduce(array: T[] | readonly T[], callback: (accumulator: T | U, currentValue: T, currentIndex: number, array: readonly T[]) => Promise, initialValue?: T | U): Promise {
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  const hadInitialValue = typeof initialValue === 'undefined';
60
  const startingIndex = hadInitialValue ? 1 : 0;
61
62
  if (typeof initialValue === 'undefined') {
63
    if (array.length === 0) {
64
      throw new TypeError('Reduce of empty array with no initial value');
65
    }
66
67
    initialValue = array[0];
68
  }
69
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  let value = initialValue;
71
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  for (let i = startingIndex; i < array.length; i++) {
73
    const v = await callback(value, array[i], i, array);
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    value = v;
75
  }
76
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  return value;
78
}

7
export function objectFromArray(arr, key = 'id') {
8
    if (arr && arr.length) {
9
      return arr.reduce((v, i) => {
10
        v[i[key]] = i;
11
        return v;
12
      }, {});
13
    }
14
    return {};
15
  }

1283
function arrayToObjectsById(array, keyOf) {
1284
    return array.reduce(function (objectsById, item) {
1285
        objectsById[keyOf(item)] = item;
1286
        return objectsById;
1287
    }, {});
1288
}

10
function arrayReduce(cb, initial, array) {
11
  var length = array.length
12
  var result = initial
13
  for (var i = 0; i < length; i++) {
14
    result = cb(result, array[i], i, array)
15
  }
16
  return result
17
}

34
function reduceArray(d) {
35
    return d.reduce(function(a, x) {
36
        return a + x;
37
    }, 0) / d.length;
38
}

80
function flatMap(array, callback) {
81
  return array.reduce((result, item) => result.concat(callback(item)), []);
82
}