101 lines
2.7 KiB
JavaScript
101 lines
2.7 KiB
JavaScript
array = ["Bilbo", "Gandalf", "Nazgul"];
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array.forEach((item, index, array) =>{
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console.log(`${item} is at index ${index} in ${array}`)
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});
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console.log(`arr.indexOf(Bilbo): ${array.indexOf("Bilbo")}`)
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console.log(`arr.indexOf(Bilbo): ${array.includes("Bilbo")}`)
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let fruits = ['Apple', 'Orange', 'Apple']
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console.log(`fruits.indexOf('Apple'): ${fruits.indexOf('Apple')}`)
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console.log(`fruits.lastIndexOf('Apple'): ${fruits.lastIndexOf('Apple')}`)
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// arr.find(fn)
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let users = [
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{id: 1, name: "xingzhesun"},
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{id: 2, name: "zhexingsun"},
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{id: 3, name: "sunxingzhe"},
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];
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let user1 = users.find(item => item.id == 1);
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let user2 = users.findLastIndex(item => item.id == 1);
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console.log(user1.name);
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console.log(user2.name);
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// arr.filter
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let someUsers = users.filter(user => user.id < 3);
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console.log(someUsers)
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someUsers = users.filter(function(item, index, array){
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if (item.id < 3){
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return true;
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}
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})
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console.log(someUsers);
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// arr.map(fn)
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let lengths = array.map(item=>item.length);
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console.log(lengths);
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// arr.sort(fn)
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function compare(a, b){
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if (a > b) return 1;
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if (a == b) return 0;
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if (a < b) return -1;
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}
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arr = [15, 2 ,1];
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console.log(`arr.sort(): ${arr.sort(compare)}`);
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console.log(`arr.sort(): ${arr.sort((a,b) => a - b)}`);
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let countries = ['Österreich', 'Andorra', 'Vietnam'];
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console.log(countries.sort((a,b) => a.localeCompare(b)))
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// arr.reverse()
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countries = countries.reverse()
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console.log(countries)
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// arr.split() and arr.join()
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let names = "Bilbo, Gandalf, Nazgul";
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let nameLists = names.split(', ');
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for(let name of nameLists){
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console.log(`A message to ${name}`);
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}
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// [LOG - 6/16/24 21:32:14] "A message to Bilbo"
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// [LOG - 6/16/24 21:32:14] "A message to Gandalf"
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// [LOG - 6/16/24 21:32:14] "A message to Nazgul"
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nameLists = names.split(', ', 2);
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for(let name of nameLists){
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console.log(`A message to ${name}`);
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}
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// [LOG - 6/16/24 21:32:14] "A message to Bilbo"
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// [LOG - 6/16/24 21:32:14] "A message to Gandalf"
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console.log(`nameLists: ${nameLists.join('; ')}`)
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// [LOG - 6/16/24 21:33:45] "nameLists: Bilbo; Gandalf"
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// arr.reduce(fn) arr.reduceRight(fn)
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let numbers = [1,2,3,4,5]
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console.log(numbers.reduce(function(sum, current){
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return sum + current;
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}, 0));
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console.log(numbers.reduce((sum, cur) => sum + cur, 0));
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console.log(numbers.reduceRight((sum, cur) => sum + cur, 0));
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// Array.isArray()
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console.log(Array.isArray(countries))
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function camelize(str){
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words = str.split('-')
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for(let i = 1; i < words.length; i++){
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words[i][0] = words[i][0].toUpperCase();
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console.log(words[i])
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}
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return words.join('');
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}
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console.log(camelize("background-color"))
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console.log(camelize("list-style-image"))
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console.log(camelize("-webkit-translation")) |