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30个Javascript知识点总结,总有你不知道的!

时间:2023-03-28 19:08:53 HTML

鏈€杩戦噸娓╃孩瀹濅功锛屽彂鐜颁簡涓€浜涙湁瓒g殑鍐欐硶銆傚緢澶氫笢瑗垮湪鏃ュ父鐢熸椿涓兘浼氱敤鍒帮紝浣嗘槸鎴戝彂鐜拌繕鏄湁涓嶅悓鐨勫啓娉曘€傜粨鍚堟棩甯稿伐浣滀腑鐢ㄥ埌鐨勪竴浜涙柟娉曪紝缁欏ぇ瀹舵€荤粨涓€绡囧笇鏈涘澶у缁忓父鐢ㄥ埌涓嶇煡閬撶殑涓滆タ鏈夋墍甯姪锛氫竴琛屼唬鐮佸畬鎴愮粨鏋勫姞璧嬪€笺€傛垜浠湪鏃ュ父鐢熸椿涓粡甯镐娇鐢ㄧ粨鏋勮祴鍊笺€傞€氬父锛屾垜浠厛鏋勯€犲啀璧嬪€笺€傚綋鐒舵垜浠篃鍙互涓€琛屽畬鎴愯В鏋勫拰璧嬪€笺€傛搷浣滅湅璧锋潵寰堢畝鍗曪紝鍙鎬у綋鐒剁煡閬擄紒letpeople={name:null,age:null};letresult={name:'寮犱笁',age:16};({name:people.name,age:people.age}=result);console.log(people)//{"name":"ZhangSan","age":16}###瑙f瀯鍩虹鏁版嵁绫诲瀷鏃ュ父鐢熸椿涓垜浠笉搴旇鐢ㄥ埌杩欐牱鐨勫満鏅紝浣嗗叾瀹炴垜浠篃鍙互瑙f瀯鍩虹鏁版嵁绫诲瀷瑙f瀯const{length:a}='1234';console.log(a)//4瀵规暟缁勮В鏋勫揩閫熻幏鍙栨渶鍚庝竴椤瑰€煎叾瀹炴垜浠彲浠ュ鏁扮粍瑙f瀯璧嬪€艰幏鍙栭暱搴﹀睘鎬э紝閫氳繃杩欎釜鐗规€т篃鍙互鍋氭洿澶氱殑浜嬫儏銆俢onstarr=[1,2,3];const{0:first,length,[length-1]:last}=arr;first;//1鏈€鍚庝竴涓紱//3闀垮害锛?/3灏嗕笅鏍囪浆鎹㈡垚涓枃闆朵竴浜屼笁...瀵逛簬鏃ュ父鐢熸椿涓彲鑳藉瓨鍦ㄧ殑鍒楄〃锛屾垜浠渶瑕佸皢瀵瑰簲鐨?12345杞崲鎴愪腑鏂囦竴浜屼笁鍥涗簲...鍦ㄨ€侀」鐩腑锛屾垜浠彲浠ョ湅鍒版湁寰堝琛屾槸鎴戜滑鑷繁鎵嬪姩瀹氫箟鐨勩€傚啓鏂规硶锛屾墍浠ユ垜鍐欎簡涓€涓繖鏍风殑鏂规硶鏉ヨ浆鎹xportfunctiontransfromNumber(number){constINDEX_MAP=['zero','one'.....]if(!number)returnif(number===10)returnINDEX_MAP[number]return[...number.toString()].reduce((pre,cur)=>pre+INDEX_MAP[cur],'')}鍒ゆ柇鏁存暟鐨勪笉鍚屾柟娉?*1.浠讳綍鏁存暟閮戒細鑳借1鏁撮櫎锛屽嵆浣欐暟涓?銆傜敤杩欎釜瑙勫垯鍒ゆ柇鏄惁鏄暣鏁般€備絾鏄浜庡瓧绗︿覆涓嶅噯纭?/functionisInteger(obj){returnobj%1===0}/*1.娣诲姞鍒ゆ柇鏄暟瀛?/functionisInteger(obj){returntypeofobj==='number'&&obj%1===0}/*2銆佺敤Math.round銆丮ath.ceil銆丮ath.floor鍒ゆ柇鏁存暟鍥涜垗浜斿叆鍚庢槸鍚︾瓑浜庤嚜韬€傚埄鐢ㄨ繖涓壒鎬у垽鏂槸鍚︽槸鏁存暟*/functionisInteger(obj){returnMath.floor(obj)===obj}/*3.浣跨敤parseInt鍒ゆ柇鏈変簺鍦烘櫙涓嶅噯纭?/functionisInteger(obj){returnparseInt(obj,10)===obj}/*4.閫氳繃浣嶈繍绠?/functionisInteger(obj){return(obj|0)===obj}/*5.ES6鎻愪緵Number.isInteger*/閫氳繃css妫€娴嬬郴缁熺殑涓婚鑹诧紝鍏ㄥ眬淇敼鏍峰紡@media鐨勫睘鎬refers-color-scheme鏉ヨ幏鐭ュ綋鍓嶇郴缁熶富棰樸€傚綋鐒讹紝鍦ㄤ娇鐢ˊmedia(prefers-color-scheme:dark){//...}@media(prefers-color-scheme:light){//...}javascript涔熷彲浠ュ緢瀹规槗鍦板仛window.addEventListener('theme-mode',event=>{if(event.mode=='dark'){}if(event.mode=='light'){}})window.matchMedia('(prefers-color-scheme:dark)').addEventListener('change',event=>{if(event.matches){}//darkmode})arraysarraysrandomlyshuffleorder閫氳繃0.5-Math.random()寰楀埌涓€涓殢鏈烘暟锛岀劧鍚巗ortshuffle涓ゆ锛屼絾鏄繖涓柟娉曞叾瀹為殢鏈烘€т笉澶燂紝濡傛灉鏄紒涓?绾у簲鐢ㄣ€傛帹鑽愪娇鐢ㄧ浜岀娲楃墝绠楁硶shuffle(arr){returnarr.sort(()=>0.5-Math.random()).sort(()=>0.5-Math.random());},functionshuffle(arr){for(leti=arr.length-1;i>0;i--){constrandomIndex=Math.floor(Math.random()*(i+1));[arr[i],arr[randomIndex]]=[arr[randomIndex],arr[i]]}returnarr}闅忔満鍙栦竴涓竷灏斿€煎拰鍓嶉潰鐨勫師鐞嗕竴鏍枫€傚畠鏄€氳繃闅忔満鏁拌幏寰楃殑銆侻ath.random()鐨勮寖鍥存槸0-0.99锛屾鐜囦负0.5鍦?0%涓棿銆俧unctionrandomBool(){return0.5-Math.random()}灏嗘暟缁勪腑鐨勭涓€椤规斁鍒版渶鍚庝竴椤筬unction(arr){returnarr.push(arr.shift());}绉诲姩鏁扮粍涓殑鏈€鍚庝竴椤瑰埌绗竴椤筬unction(arr){returnarr.unshift(arr.pop());}浣跨敤set鏁扮粍鍘婚噸functionuniqueArr(arr){return[...newSet(arr)]}绌烘牸鐩稿叧锛屾洿澶氱煡璇嗙偣璇峰弬鑰凁煈夛細寮€鍙戣€呯綉绔?-30涓狫avaScript鐭ヨ瘑鐐?/p>