Try implementing an alternative to using flatMap in JavaScript

Question

Try implementing an alternative to using flatMap in JavaScript

Looking for an alternative method to achieve the same functionality as flatmap in JavaScript with lower ES5 version for the following mapping.

const b = [{
  "errorname": [{
    "name": "Error 01",
    "desc_1": "Test: 01",
    "desc_2": "Testing"
  }, {
    "name": "Error 03",
    "desc_1": "Test: 03",
    "desc_2": "Testing"
  }],
}, {
  "errorname": [{
    "name": "Error 02",
    "desc_1": "Test: 02",
    "desc_2": "Testing"
  }, {
    "name": "Error 09",
    "desc_1": "Test: 09",
    "desc_2": "Testing"
  } ]
}];

var errorMap = generateErrorMap(b);

function generateErrorMap(arr){
  var newArray = [];
  arr.forEach(function(elem){
    elem.errorname.forEach(function(error){
      var tempObj = {};
      tempObj[error.name] = {desc_1: error.desc_1, desc_2: error.desc_2};
      newArray.push(tempObj);
    });
  });
  
  return newArray;
}

console.log(errorMap)

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

Exploring options for ES5 compatibility with similar operations. The application is accessed using an electron app that does not support ES9.

javascript

Answer 1

Answer №1

If you need to use the flatMap function in your code, there are a couple of options available to you. You can either download a polyfill or create your own implementation. Here is an example of how you could implement it:

Array.prototype.flatMap = function(mapper) {
  var result = [];

  for (var i = 0; i < this.length; ++i) {
    var item = mapper(this[i], i, this);

    if (!Array.isArray(item)) {
      item = [item];
    }

    for (var j = 0; j < item.length; ++j) {
      result.push(item[j]);
    }
  }

  return result;
}

Once you have implemented this, you will be able to call myArray.flatMap just like you would with any other array method.

Answer 2

If you need to use the flatMap function in your code, there are a couple of options available to you. You can either download a polyfill or create your own implementation. Here is an example of how you could implement it:

Array.prototype.flatMap = function(mapper) {
  var result = [];

  for (var i = 0; i < this.length; ++i) {
    var item = mapper(this[i], i, this);

    if (!Array.isArray(item)) {
      item = [item];
    }

    for (var j = 0; j < item.length; ++j) {
      result.push(item[j]);
    }
  }

  return result;
}

Once you have implemented this, you will be able to call myArray.flatMap just like you would with any other array method.

Answer 3

Answer №2

To implement an inner-outer reduce, you can nest the calls within each other. This approach is suitable for ECMAScript versions before 5/6.

const b = [{
  "errorname": [
    { "name": "Error 01", "desc_1": "Test: 01", "desc_2": "Testing" },
    { "name": "Error 03", "desc_1": "Test: 03", "desc_2": "Testing" }],
}, {
  "errorname": [
    { "name": "Error 02", "desc_1": "Test: 02", "desc_2": "Testing" },
    { "name": "Error 09", "desc_1": "Test: 09", "desc_2": "Testing" }
  ]
}];

var errorMap = b.reduce(function(outer, group) {
  return group.errorname.reduce(function(inner, item) {
    return inner.set(item.name, {
      desc_1: item.desc_1,
      desc_2: item.desc_2
    });
  }, outer);
}, new Map);

console.log(Object.fromEntries([...errorMap]));

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

Answer 4

To implement an inner-outer reduce, you can nest the calls within each other. This approach is suitable for ECMAScript versions before 5/6.

const b = [{
  "errorname": [
    { "name": "Error 01", "desc_1": "Test: 01", "desc_2": "Testing" },
    { "name": "Error 03", "desc_1": "Test: 03", "desc_2": "Testing" }],
}, {
  "errorname": [
    { "name": "Error 02", "desc_1": "Test: 02", "desc_2": "Testing" },
    { "name": "Error 09", "desc_1": "Test: 09", "desc_2": "Testing" }
  ]
}];

var errorMap = b.reduce(function(outer, group) {
  return group.errorname.reduce(function(inner, item) {
    return inner.set(item.name, {
      desc_1: item.desc_1,
      desc_2: item.desc_2
    });
  }, outer);
}, new Map);

console.log(Object.fromEntries([...errorMap]));

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

Try implementing an alternative to using flatMap in JavaScript

Answer №1

Answer №2

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