Summary of what we did to make JavaScript compatible with IE11

Suddenly asked for IE11 support

I will summarize the parts that I, a JavaScript beginner, struggled with when asked to support IE11. I have posted the code before and after the correction, so I hope it will be helpful.

Arrow function

Corresponding code

$button.click((event) => {
    alert('I pressed the button');
});

// => SCRIPT1002:Syntax error.

Modified code

$button.click(function(event) {
    console.log('I pressed the button');

// =>I pressed the button
});

Template literal

The one that expands variables in a string enclosed in back quotes

Corresponding code

const age = 20
console.log(`My age is${age}is.`);

// => SCRIPT1014:The characters are incorrect.

Modified code

const age = 20;
console.log('My age is' + age + 'is.');

// =>My age is 20

isNaN It seems to be a method that evaluates whether the argument is non-number

Corresponding code

const int = 1000;
console.log(Number.isNaN(int));

// => SCRIPT438:The object is'isNaN'Does not support properties or methods.

Modified code

const int = 1000;
console.log(isNaN(int));

// => false

.find()

Corresponding code

const fruits = ['Apple', 'Orange', 'Banana']
if(fruits.find(function (fruit) {return fruit === 'Grape'})) {
  console.log('It's an apple!');
}else {
  console.log('It's not an apple!');
}

// => SCRIPT438:The object is'find'Does not support properties or methods.

Modified code

function sample(arg) {
    const fruits = ['Apple', 'Orange', 'Banana']
    if(fruits.filter(function (fruit) {return fruit === arg})[0]) {
      console.log('It's a crap!');
    }else {
      console.log('It's not a crap!');
    }
}

sample('Banana')
sample('Tomato')

// =>It's a crap!
// =>It's not a crap!

2020/11/12 postscript

indexOf is easier to write

function sample(arg) {
    const fruits = ['Apple', 'Orange', 'Banana']
    if(fruits.indexOf(arg) !== -1) {
      console.log('It's a crap!');
    }else {
      console.log('It's not a crap!');
    }
}

sample('Banana')
sample('Tomato')

// =>It's a crap!
// =>It's not a crap!

@ il9437 Thank you for pointing out m (_ _) m

version information

IE: 11.418.18362.0

Please comment if you have any advice, such as "I should do this more!" Or "There is also such a way of writing!" M (_ _) m

Recommended Posts

Summary of what we did to make JavaScript compatible with IE11
Make Nginx of CentOS8 SSL compatible with Let's Encrypt
Summary of how to use the proxy set in IE when connecting with Java
What is an immutable object? [Explanation of how to make]
Summary of problems and countermeasures when operating IE with WebDriver of Selenium2
[Rails] Make pagination compatible with Ajax
Summary of means when you want to communicate with HTTP on Android