Nodejs Utililty Methods Array Concatenate Map

Array.prototype.concatMap = function() {
  return this.map(function(item) {
      return projectionFunction(item);
    }).concatAll();
};

'use strict';
Array.prototype.concatMap = function (cb) {
    return this.map(cb).concatAll()

'use strict';
var j = require('junify');
Array.prototype.concatMap = function (f) {
  return Array.prototype.concat.apply([], this.map(f));
};
j.matchesAny = function (patterns) {
  return function (it) {
    return patterns.some(function (pattern) {
      return  j.unify(pattern, it);
...

'use strict';
let j = require('junify');
Array.prototype.concatMap = function (f) {
  return Array.prototype.concat.apply([], this.map(f));
};
j.matchesAny = function (patterns) {
  return (it) => patterns.some(pattern => j.unify(pattern, it));
};
j.match = function (arg, cases) {
...

Array.prototype.concatMap = function(fn) {
    return this
        .map((item, index, arr) => fn(index))
        .concatAll();
};

Array.prototype.concatMap = function (modifierFunction) {
    return this.map(modifierFunction).concatAll();

Array.prototype.concatMap = function(projectionFunction){
  return this.map(function(item){
    return projectionFunction(item);
  }).concatAll();

Array.prototype.concatMap = function (projectionFunctionThatReturnsArray) {
  return this.
    map(function (item) {
      return projectionFunctionThatReturnsArray(item);
    }).
    concatAll();
};

Array.prototype.concatMap = function(projectionFunctionThatReturnsArray) {
  return this.
    map(function(item) {
      return this.map((i) => {
        return i;
      }).concatAll();
    }).
    concatAll();
};
...

Array.prototype.concatMap = function(projectionFunctionThatReturnsArray) {
  return this.
    map(function(item) {
      return projectionFunctionThatReturnsArray(item);
    }).
    concatAll();
};