鏂规硶涓€鍖呮嫭methodletarr=['A','B','C','D']console.log(arr.includes('A'))//trueconsole.log(arr.includes('浜?))//falsemethod2indexOfmethodletarr=['A','B','C','D']console.log(arr.indexOf('A'))//0锛堝鏋滄湁锛宺eturntheindex0~n)console.log(arr.indexOf('浜?))//-1(娌℃湁鍒欒繑鍥?1)鏂规硶涓塮indIndexmethodletarr=['A','B','C','D']letflag1=arr.findIndex((item)=>{returnitem=='A'})console.log(flag1)//0锛堝鏋滄湁鍒欒繑鍥炵储寮?~n锛塴etflag2=arr.findIndex((item)=>{returnitem=='浜?})console.log(flag2)//-1锛堟病鏈夊垯杩斿洖-1锛墂ay4somemethodletarr=['A','B','C','D']letflag3=arr.some((item)=>{//鍙鏈変竴涓氨杩斿洖truereturnitem=='A'})console.log(flag3)//trueletflag4=arr.some((item)=>{//falsereturnitem=='浜?})console.log(flag4)//false鏂规硶浜斿畾涔塴ogo鍔犲叕鍏卞惊鐜?/definelogo寰幆for,forEach...letarr=['A','B','C','D']letflag5=false//榛樿涓嶅瓨鍦╝rr.forEach((item)=>{if(item=='A'){//flag5=true}})console.log(flag5)//true//false娉ㄦ剰绠€鍗曞ぇ鎵逛娇鐢╥ncludes鎴杋ndexOf绫讳技浜庤繖涓畝鍗曠殑鏁扮粍锛屾暟缁勪腑鍙湁涓€椤癸紝鍐呴儴瀛樺偍瀛楃涓叉垨鏁板瓧绛夛紝浣跨敤includes鎴杋ndexOf鏂逛究涓€浜沘rr=[1,2,3,4,5]arr2=['Fortune','WhiteSkin','RedMiddle']瀵逛簬鏇村鏉傜殑鏁扮粍锛屼娇鐢ㄥ叾浠栨暟缁勶紝渚嬪灞傛鏁扮粍銆佹暟缁勪腑鐨勫璞℃垨鏇村灞傛缁撴瀯銆傝繖鏃跺€欏氨闇€瑕佺敤鍒板甫鏈夊洖璋冨嚱鏁扮殑鏂规硶銆傝繖鏃跺€欑敤includes鎴栬€卛ndexOfarr3=[{name:'瀛欐偀绌?,age:500},{name:'鐚叓鎴?,age:88},{name:'鍜屽皻娌?,age:1000},]闈㈣瘯棰橈細includes鍜宨ndexOf鏈€澶х殑鍖哄埆馃槀鏈€澶х殑鍖哄埆鏄痠ndexOf鏄?==includes鏄?=indexOf鏄弗鏍肩殑锛屼笉鑳芥纭垽鏂暟缁勪腑鏄惁鏈塏aN锛屼絾鏄痠ncludes鍙互璁゛rr=[NaN,1,undefined]console.log(arr.includes(NaN))//trueconsole.log(arr.indexOf(NaN))//-1//undefined涓嶅彈褰卞搷console.log(arr.includes(undefined))//trueconsole.log(arr.indexOf(undefined))//2鍐呭績鎯虫硶锛氶潰璇曞畼锛屼綘骞虫椂寮€鍙戜笟鍔★紝瀹氫箟涓€涓暟缁勶紝閲岄潰瀛樻斁NaN鍚楋紵(鈭樷伡檀鈨櫶€藰锔匪樷伡檀鈨櫶佲垬)
