1 00:00:03,820 --> 00:00:04,900 This video. 2 00:00:04,930 --> 00:00:12,250 Let's talk about if we that is immediately invoked function expression. 3 00:00:12,820 --> 00:00:18,610 So if you functions a function that is executed as soon as it is created. 4 00:00:19,000 --> 00:00:19,600 Wow. 5 00:00:19,600 --> 00:00:22,360 So what are some of the use cases here? 6 00:00:22,390 --> 00:00:30,070 Well, let's assume that you want a function that's going to be executed as soon as your page load. 7 00:00:30,100 --> 00:00:37,100 Then we need what is called if and for if it functions to it, execute once and that is all. 8 00:00:37,120 --> 00:00:44,560 So let's see how we are going to implement if it functions well, this idea or concept is commonly used 9 00:00:44,560 --> 00:00:45,690 in redux. 10 00:00:45,700 --> 00:00:48,480 If you are familiar with React and Redux, go. 11 00:00:48,520 --> 00:00:53,650 So let's see how you're are going to create a function called iffy and let's see how it's going to be 12 00:00:53,650 --> 00:00:54,370 invoked. 13 00:00:54,700 --> 00:01:00,670 We are going to create a simple function and for the meantime let's create our normal function. 14 00:01:00,670 --> 00:01:08,180 And then we call it, and let's see how we can pass our custom function to an F function to be called. 15 00:01:08,200 --> 00:01:12,640 So let's see, the first function is going to be log. 16 00:01:13,000 --> 00:01:15,640 Hello, very simple function. 17 00:01:15,940 --> 00:01:16,450 Look. 18 00:01:16,450 --> 00:01:16,810 Hello. 19 00:01:16,810 --> 00:01:21,040 And this function will take in anything good. 20 00:01:21,040 --> 00:01:23,050 So here, just console.log. 21 00:01:23,870 --> 00:01:26,420 Let's say this one are going to be. 22 00:01:26,450 --> 00:01:27,740 Hello, this is. 23 00:01:27,740 --> 00:01:29,180 Hello, normal function. 24 00:01:30,050 --> 00:01:31,100 This a normal function. 25 00:01:31,100 --> 00:01:31,490 Right. 26 00:01:31,490 --> 00:01:35,660 So if I call this function called log. 27 00:01:35,660 --> 00:01:40,910 Hello indeed I won't to see as normal function down in my console. 28 00:01:41,120 --> 00:01:43,580 So let's see how we are going to create. 29 00:01:43,580 --> 00:01:50,450 If function well, we can do so using normal function, syntax or arrow function and we are going to 30 00:01:50,450 --> 00:01:52,280 adopt these two techniques. 31 00:01:52,280 --> 00:01:54,650 So let's start from using normal function. 32 00:01:54,650 --> 00:01:57,410 So using, let's say F. 33 00:01:57,890 --> 00:02:01,910 So the first step is bring in your parentheses as that. 34 00:02:01,910 --> 00:02:05,660 And then inside this, that's where we are going to create our function. 35 00:02:05,660 --> 00:02:11,600 So let's say function and this function will have no name as this. 36 00:02:12,170 --> 00:02:18,350 So if I open my services, I can log anything here to the console and let's see. 37 00:02:18,560 --> 00:02:23,180 So if I save it, nothing happens because we're not calling this function, right? 38 00:02:23,180 --> 00:02:29,150 So to call it you bring your syntax as that if I save it. 39 00:02:29,160 --> 00:02:34,490 Nine See that if we see that it has been called automatically down here. 40 00:02:34,850 --> 00:02:36,830 So what about if I give it a name? 41 00:02:36,830 --> 00:02:39,830 Let's say say hello. 42 00:02:43,000 --> 00:02:43,840 As that. 43 00:02:43,840 --> 00:02:46,700 So if I save this one, indeed I see. 44 00:02:46,720 --> 00:02:47,120 Say hello. 45 00:02:47,200 --> 00:02:53,590 Because if this function is going to call immediately, I think giving it a name doesn't make sense 46 00:02:53,590 --> 00:02:57,120 to me, but it's also depends how you want it. 47 00:02:57,130 --> 00:03:03,940 Maybe in future you want to know what kind of function or which logic that if it doing so you can pass 48 00:03:03,940 --> 00:03:06,640 in or you can give it a name through it. 49 00:03:06,640 --> 00:03:13,060 So we can also call any function inside this particular function. 50 00:03:13,060 --> 00:03:19,330 So let's say that you want a function that's going to be called automatically so I can bring in my log. 51 00:03:19,330 --> 00:03:19,840 Hello. 52 00:03:19,840 --> 00:03:21,400 Inside, look. 53 00:03:21,400 --> 00:03:22,000 Hello. 54 00:03:22,150 --> 00:03:23,890 Is that if I save it? 55 00:03:23,890 --> 00:03:24,850 And now it's that? 56 00:03:24,850 --> 00:03:25,270 Hello. 57 00:03:25,270 --> 00:03:32,620 I'm normal function but instead we pass in this normal function to our function to your code. 58 00:03:32,620 --> 00:03:36,670 So let's see how we can create this one using arrow function. 59 00:03:36,670 --> 00:03:38,470 The syntax will be crazy. 60 00:03:38,470 --> 00:03:39,250 So let's see. 61 00:03:39,880 --> 00:03:47,530 So now remember we bring in our parentheses as that and inside goes my function and here we go, arrow 62 00:03:47,530 --> 00:03:48,400 function. 63 00:03:48,400 --> 00:03:55,090 And this function is going to retain an expression so I can ignore the basis so I can even console.log 64 00:03:55,090 --> 00:03:55,840 anything. 65 00:03:55,870 --> 00:04:00,160 Let's say I know that if we. 66 00:04:01,270 --> 00:04:02,200 As that. 67 00:04:02,200 --> 00:04:07,060 And if I save it, you see that nothing happened because I didn't call this function. 68 00:04:07,060 --> 00:04:10,450 So I'll break my parentheses as that when I save it. 69 00:04:10,810 --> 00:04:19,269 Well, nothing happens because I need to wrap this one inside a parentheses as that because I forgot 70 00:04:19,269 --> 00:04:24,180 to wrap it inside as that when I save it. 71 00:04:24,560 --> 00:04:26,640 You see that another iffy. 72 00:04:26,830 --> 00:04:27,350 Great. 73 00:04:27,370 --> 00:04:34,870 Remember, I have to wrap everything inside that parentheses, and after that I bring a parentheses 74 00:04:34,870 --> 00:04:36,910 to call the function as that. 75 00:04:36,910 --> 00:04:38,740 So it is what you call if.