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@yashikagarg13
Last active March 18, 2017 06:05
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Updating list without mutating it using slice(), concat() and spread (...)
<!DOCTYPE html>
<html>
<head>
<meta charset="utf-8">
<meta name="viewport" content="width=device-width">
<title>JS Bin</title>
<script src="https://npmcdn.com/expect/umd/expect.min.js"></script>
<script src="https://wzrd.in/standalone/deep-freeze@latest"></script>
</head>
<body>
<div id="root"></div>
<script id="jsbin-javascript">
"use strict";
function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) arr2[i] = arr[i]; return arr2; } else { return Array.from(arr); } }
var addCounter = function addCounter(list) {
var initialState = 0;
return [].concat(_toConsumableArray(list), [0]);
// return list.concat([initialState])
};
var removeCounter = function removeCounter(list, index) {
return [].concat(_toConsumableArray(list.slice(0, index)), _toConsumableArray(list.slice(index + 1)));
};
var incrementCounter = function incrementCounter(list, index) {
var counterState = list[index] + 1;
return [].concat(_toConsumableArray(list.slice(0, index)), [counterState], _toConsumableArray(list.slice(index + 1)));
};
var decrementCounter = function decrementCounter(list, index) {
var counterState = list[index] - 1;
return [].concat(_toConsumableArray(list.slice(0, index)), [counterState], _toConsumableArray(list.slice(index + 1)));
};
var testAddCounter = function testAddCounter() {
var listBefore = [];
var listAfter = [0];
deepFreeze(listBefore);
expect(addCounter(listBefore)).toEqual(listAfter);
};
var testRemoveCounter = function testRemoveCounter() {
var listBefore = [0, 10, 1];
var listAfter = [0, 1];
deepFreeze(listBefore);
expect(removeCounter(listBefore, 1)).toEqual(listAfter);
};
var testIncrementCounter = function testIncrementCounter() {
var listBefore = [0, 10, 1];
var listAfter = [0, 11, 1];
deepFreeze(listBefore);
expect(incrementCounter(listBefore, 1)).toEqual(listAfter);
};
var testDecrementCounter = function testDecrementCounter() {
var listBefore = [0, 10, 1];
var listAfter = [0, 9, 1];
deepFreeze(listBefore);
expect(decrementCounter(listBefore, 1)).toEqual(listAfter);
};
testAddCounter();
testRemoveCounter();
testIncrementCounter();
testDecrementCounter();
console.log("Test passed!!");
</script>
<script id="jsbin-source-javascript" type="text/javascript">const addCounter = (list) => {
let initialState = 0;
return [...list, 0];
// return list.concat([initialState])
}
const removeCounter = (list, index) => {
return [...list.slice(0, index),
...list.slice(index + 1)]
}
const incrementCounter = (list, index) => {
const counterState = list[index] + 1;
return [...list.slice(0, index),
counterState,
...list.slice(index + 1)]
}
const decrementCounter = (list, index) => {
const counterState = list[index] - 1;
return [...list.slice(0, index),
counterState,
...list.slice(index + 1)]
}
const testAddCounter = () => {
const listBefore = [];
const listAfter = [0];
deepFreeze(listBefore);
expect(addCounter(listBefore)).toEqual(listAfter);
}
const testRemoveCounter = () => {
const listBefore = [0, 10, 1];
const listAfter = [0, 1];
deepFreeze(listBefore);
expect(removeCounter(listBefore, 1)).toEqual(listAfter);
}
const testIncrementCounter = () => {
const listBefore = [0, 10, 1];
const listAfter = [0, 11, 1];
deepFreeze(listBefore);
expect(incrementCounter(listBefore, 1)).toEqual(listAfter);
}
const testDecrementCounter = () => {
const listBefore = [0, 10, 1];
const listAfter = [0, 9, 1];
deepFreeze(listBefore);
expect(decrementCounter(listBefore, 1)).toEqual(listAfter);
}
testAddCounter();
testRemoveCounter();
testIncrementCounter();
testDecrementCounter();
console.log("Test passed!!");
</script></body></script>
</html>
"use strict";
function _toConsumableArray(arr) { if (Array.isArray(arr)) { for (var i = 0, arr2 = Array(arr.length); i < arr.length; i++) arr2[i] = arr[i]; return arr2; } else { return Array.from(arr); } }
var addCounter = function addCounter(list) {
var initialState = 0;
return [].concat(_toConsumableArray(list), [0]);
// return list.concat([initialState])
};
var removeCounter = function removeCounter(list, index) {
return [].concat(_toConsumableArray(list.slice(0, index)), _toConsumableArray(list.slice(index + 1)));
};
var incrementCounter = function incrementCounter(list, index) {
var counterState = list[index] + 1;
return [].concat(_toConsumableArray(list.slice(0, index)), [counterState], _toConsumableArray(list.slice(index + 1)));
};
var decrementCounter = function decrementCounter(list, index) {
var counterState = list[index] - 1;
return [].concat(_toConsumableArray(list.slice(0, index)), [counterState], _toConsumableArray(list.slice(index + 1)));
};
var testAddCounter = function testAddCounter() {
var listBefore = [];
var listAfter = [0];
deepFreeze(listBefore);
expect(addCounter(listBefore)).toEqual(listAfter);
};
var testRemoveCounter = function testRemoveCounter() {
var listBefore = [0, 10, 1];
var listAfter = [0, 1];
deepFreeze(listBefore);
expect(removeCounter(listBefore, 1)).toEqual(listAfter);
};
var testIncrementCounter = function testIncrementCounter() {
var listBefore = [0, 10, 1];
var listAfter = [0, 11, 1];
deepFreeze(listBefore);
expect(incrementCounter(listBefore, 1)).toEqual(listAfter);
};
var testDecrementCounter = function testDecrementCounter() {
var listBefore = [0, 10, 1];
var listAfter = [0, 9, 1];
deepFreeze(listBefore);
expect(decrementCounter(listBefore, 1)).toEqual(listAfter);
};
testAddCounter();
testRemoveCounter();
testIncrementCounter();
testDecrementCounter();
console.log("Test passed!!");
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