EN
JavaScript - create and use functions
7 points
In this article, we would like to show you how to create and use functions in JavaScript.
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var action1 = Function('console.log("This is my message...");');2
var action2 = Function('console.log(arguments);');3
var action3 = new Function('console.log("This is my message...");');4
var action4 = new Function('console.log(arguments);');5
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action1();7
action2(1, 2, 3, 'test 1', 'text 2', 'text n');8
action3();9
action4(1, 2, 3, 'test 1', 'text 2', 'text n');10
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console.log(action1.name);12
console.log(action2.name);13
console.log(action3.name);14
console.log(action4.name);Output (with NodeJS):
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This is my message...2
3
[Arguments] {4
'0': 1,5
'1': 2,6
'2': 3,7
'3': 'test 1',8
'4': 'text 2',9
'5': 'text n'10
}11
12
This is my message...13
14
[Arguments] {15
'0': 1,16
'1': 2,17
'2': 3,18
'3': 'test 1',19
'4': 'text 2',20
'5': 'text n' 21
}22
23
anonymous24
anonymous25
anonymous26
anonymousxxxxxxxxxx1
var action = function() {2
console.log('This is my message...');3
};4
5
var sum1 = function(a, b) {6
return a + b;7
};8
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var sum2 = function() {10
var result = 0;11
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for(var i = 0; i < arguments.length; ++i) {13
result += arguments[i];14
}15
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return result;17
};18
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var print = function(a, b) {20
var text = '';21
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text += 'a=' + a + ', ';23
text += 'b=' + b + ', ';24
text += 'arguments=[';25
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for(var i = 0; i < arguments.length; ++i) {27
if(i > 0) {28
text += ', ';29
}30
text += arguments[i];31
}32
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text += ']';34
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console.log(text);36
};37
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action();40
console.log(sum1(1, 2));41
console.log(sum2(1, 2, 3, 4, 5));42
print(1, 2, 3, 4, 5);43
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console.log(action.name);45
console.log(sum1.name);46
console.log(sum2.name);47
console.log(print.name);Output (with NodeJS):
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This is my message...2
33
154
a=1, b=2, arguments=[1, 2, 3, 4, 5]5
6
action7
sum18
sum29
printxxxxxxxxxx1
var action = function MyFunctionName() {2
console.log('This is my message...');3
};4
5
var sum1 = function MyFunctionName(a, b) {6
return a + b;7
};8
9
var sum2 = function MyFunctionName(a, b) {10
var result = 0;11
12
for(var i = 0; i < arguments.length; ++i) {13
result += arguments[i];14
}15
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return result;17
};18
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var print = function MyFunctionName(a, b) {20
var text = '';21
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text += 'a=' + a + ', ';23
text += 'b=' + b + ', ';24
text += 'arguments=[';25
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for(var i = 0; i < arguments.length; ++i) {27
if(i > 0) {28
text += ', ';29
}30
text += arguments[i];31
}32
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text += ']';34
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console.log(text);36
};37
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action();40
console.log(sum1(1, 2));41
console.log(sum2(1, 2, 3, 4, 5));42
print(1, 2, 3, 4, 5);43
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console.log(action.name);45
console.log(sum1.name);46
console.log(sum2.name);47
console.log(print.name);Output (with NodeJS):
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This is my message...2
33
154
a=1, b=2, arguments=[1, 2, 3, 4, 5]5
6
MyFunctionName7
MyFunctionName8
MyFunctionName9
MyFunctionNameArrow function has been introduced in ES6. This part shows in a simple way how to use arrow functions.
3.1. With function body in brackets
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var action1 = () => {2
console.log('This is my message...');3
};4
5
var action2 = (myArguments) => {6
console.log(myArguments);7
};8
9
var sum = (a, b) => {10
return a + b;11
};12
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var print = (a, b, myArguments) => {14
var text = '';15
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text += 'a=' + a + ', ';17
text += 'b=' + b + ', ';18
text += 'myArguments=[';19
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for(var i = 0; i < myArguments.length; ++i) {21
if(i > 0) {22
text += ', ';23
}24
text += myArguments[i];25
}26
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text += ']';28
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console.log(text);30
};31
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action1();34
action2(1, 2, 3, 4, 5);35
console.log(sum(1, 2));36
print(1, 2, 3, 4, 5);37
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console.log(action1.name);39
console.log(action2.name);40
console.log(sum.name);41
console.log(print.name);Output (with NodeJS):
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This is my message...2
[ 1, 2, 3, 4, 5 ]3
34
a=1, b=2, myArguments=[3, 4, 5]5
6
action17
action28
sum9
print3.2. Without brackets - with auto-returning of values
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var action = () => console.log('This is my message...');2
3
var print1 = text => console.log(text);4
var print2 = (myArguments) => console.log(myArguments);5
var print3 = (a, b, myArguments) => console.log(a, b, myArguments);6
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var sum = (a, b) => a + b;8
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action();11
print1('This is my custom text...');12
print2(1, 2, 3, 4, 5);13
print3(1, 2, 3, 4, 5);14
console.log(sum(1, 2));15
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console.log(action.name);17
console.log(print1.name);18
console.log(print2.name);19
console.log(print3.name);20
console.log(sum.name);Output (with NodeJS):
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This is my message...2
This is my custom text...3
[ 1, 2, 3, 4, 5 ]4
1 2 [ 3, 4, 5 ]5
36
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action8
print19
print210
print311
sumThe ways how to call function (method) has been described in this article.
