1 00:00:00,270 --> 00:00:03,210 Let me show you how I'm going to solve this challenge. 2 00:00:03,240 --> 00:00:11,520 It says that, right, a function that takes in an array of numbers and returns the sum of all the numbers 3 00:00:11,520 --> 00:00:12,360 in the array. 4 00:00:12,660 --> 00:00:16,440 So come down here as my solution. 5 00:00:17,570 --> 00:00:19,100 Solution here. 6 00:00:19,130 --> 00:00:20,300 And here we go. 7 00:00:20,450 --> 00:00:21,660 So counts. 8 00:00:21,680 --> 00:00:27,440 Let me assign the sum of all numbers. 9 00:00:27,770 --> 00:00:28,490 Every. 10 00:00:28,790 --> 00:00:30,860 So I want to sum up these numbers. 11 00:00:30,860 --> 00:00:37,160 Let's say one, two, five, six, nine, and they say two. 12 00:00:37,550 --> 00:00:41,090 So I want to sum up these arrays of numbers. 13 00:00:41,480 --> 00:00:43,220 So my function goes like this. 14 00:00:43,250 --> 00:00:46,610 Function and then sum. 15 00:00:48,310 --> 00:00:49,240 Copy this one. 16 00:00:49,420 --> 00:00:50,440 Some. 17 00:00:52,320 --> 00:00:52,710 Yeah. 18 00:00:52,710 --> 00:00:57,540 This one some of some of our away numbers function. 19 00:00:58,140 --> 00:01:01,420 And then I would it would take in the array. 20 00:01:01,440 --> 00:01:02,710 And next is. 21 00:01:02,730 --> 00:01:03,780 Here we go. 22 00:01:04,500 --> 00:01:10,430 So here comes a logic we need to use reduce method to get this one done. 23 00:01:10,440 --> 00:01:12,420 And how does it work? 24 00:01:12,450 --> 00:01:24,750 So we can say that const twitter is equal to the array our pass in as that on that I will use reduce 25 00:01:25,860 --> 00:01:29,790 and then remember I reduce our pass in my callback function. 26 00:01:30,970 --> 00:01:33,640 And my parentheses. 27 00:01:33,640 --> 00:01:37,300 The second argument is my initial variable value zero. 28 00:01:37,660 --> 00:01:45,310 So here I have access to my accumulator and my my current element or current value. 29 00:01:46,930 --> 00:01:47,710 In that. 30 00:01:48,160 --> 00:01:53,170 So if I save it now up in my parentheses, then I will say that. 31 00:01:53,170 --> 00:01:55,390 Well, retain. 32 00:01:56,630 --> 00:02:00,200 Accumulator plus my current value. 33 00:02:00,830 --> 00:02:01,640 That is it. 34 00:02:01,790 --> 00:02:06,620 So this function must return the results coming back from this. 35 00:02:07,960 --> 00:02:20,200 So after my reduced function down here, then I would say retain it, retain the total as that. 36 00:02:20,470 --> 00:02:22,600 And that is that and that is it. 37 00:02:22,840 --> 00:02:23,530 Right. 38 00:02:23,530 --> 00:02:25,060 So let's check it out. 39 00:02:25,090 --> 00:02:27,580 Let's assign the result. 40 00:02:27,580 --> 00:02:34,180 Let me say cost and sum is equal to sum of all. 41 00:02:34,180 --> 00:02:38,260 Every function I'll pass in sum of all arrays. 42 00:02:39,580 --> 00:02:43,090 I think I have declared the answer somewhere else here. 43 00:02:44,760 --> 00:02:45,390 Yeah. 44 00:02:45,660 --> 00:02:45,990 Yeah. 45 00:02:45,990 --> 00:02:47,820 I think the answer to. 46 00:02:48,330 --> 00:02:48,640 Yeah. 47 00:02:48,660 --> 00:02:49,240 No no no. 48 00:02:49,560 --> 00:02:52,740 As and start to. 49 00:02:53,170 --> 00:02:56,700 Okay so let's console.log the answer to. 50 00:02:58,830 --> 00:02:59,760 There you go. 51 00:02:59,790 --> 00:03:05,730 We have for the three if we add one plus this plus this plus this plus this is equal to the. 52 00:03:06,240 --> 00:03:08,400 That is it about the function. 53 00:03:08,820 --> 00:03:12,870 And this function can be simplified in a simple way. 54 00:03:13,050 --> 00:03:19,200 So instead of doing this one this way, we can quickly let me comment out this maybe for future references. 55 00:03:19,350 --> 00:03:30,180 So here I can do on one line by saying that I would take my array and then dot dot, reduce. 56 00:03:31,050 --> 00:03:33,120 Then I'll pass in my function. 57 00:03:34,050 --> 00:03:35,250 Brenda says. 58 00:03:35,490 --> 00:03:43,330 And next is, if I'm returning something from this immediately, I can do it in this way on one line. 59 00:03:43,350 --> 00:03:46,980 Don't worry, if you go about a random script, I will show you the syntax for this. 60 00:03:47,220 --> 00:03:48,870 But I think every function. 61 00:03:48,870 --> 00:03:49,490 Right. 62 00:03:49,500 --> 00:03:55,560 But for the meantime, because we are not having to tackle about every function, this one will not 63 00:03:55,560 --> 00:04:01,470 work for you, meaning you will not understand, but for advanced developers. 64 00:04:01,560 --> 00:04:02,580 Okay, follow me. 65 00:04:02,610 --> 00:04:05,240 So this one going to be. 66 00:04:05,280 --> 00:04:10,680 And now here I can return a account plus the current. 67 00:04:11,220 --> 00:04:12,050 And that is it. 68 00:04:12,060 --> 00:04:14,660 You see, I still see the same result. 69 00:04:14,670 --> 00:04:18,060 So this line of code can be simplified as this. 70 00:04:19,380 --> 00:04:21,420 That is it the next video? 71 00:04:21,630 --> 00:04:25,130 Let's have a look at our next coding challenge.