ํ౯ժᵱᥝᶋහ꧊୮֢හֵአ҅ྲইහᬩᓒԅྌ ES5 ᥢࣁ 9.3 ᜓԎԧು
֢ ToNumber
ҁ1҂Undefined ᔄࣳጱ꧊ഘԅ NaN
ҁ2҂Null ᔄࣳጱ꧊ഘԅ 0
ҁ3҂Boolean ᔄࣳጱ꧊҅true ഘԅ 1҅false ഘԅ 0
ҁ4҂String ᔄࣳጱ꧊ഘইݶֵአ Number() ڍහᬰᤈഘ҅ইຎ۱ތᶋහ꧊ڞഘԅ
NaN҅ᑮᒧԀԅ 0
ҁ5҂Symbol ᔄࣳጱ꧊ӧᚆഘԅහ҅տಸᲙ
ҁ6҂ҁ۱ೡහᕟ҂տḒضᤩഘԅፘଫጱᔄࣳ꧊҅ইຎᬬࢧጱฎᶋහጱᔄࣳ꧊҅
ڞٚ᭽զӤᥢڞٌ୩ګഘԅහ
ԅԧ꧊ഘԅፘଫጱᔄࣳ꧊҅ು֢ ToPrimitive տḒضҁ᭗ᬦٖ᮱֢
DefaultValue҂༄ັᧆ꧊ฎވํvalueOf() ොဩ
ইຎํଚӬᬬࢧᔄࣳ꧊ֵ҅አᧆ꧊ᬰᤈ୩ګᔄࣳഘইຎဌํֵአtoString() ጱᬬࢧ꧊
ҁইຎࣁ҂ᬰᤈ୩ګᔄࣳഘ.ইຎ valueOf() toString() ࣐ӧᬬࢧᔄࣳ꧊҅տԾኞ
TypeError Კ
JSํپᐿොဩڣෙݒᰁጱᔄࣳҘ
(1) ֵአtypeof༄ၥ ୮ᵱᥝڣෙݒᰁฎވฎnumber, string, boolean, function, undefinedᒵᔄࣳ
҅ݢզֵአtypeofᬰᤈڣෙ
(2) ֵአinstanceof༄ၥ instanceof ᬩᓒᒧӨ typeof ᬩᓒᒧፘ֒҅አԭᦩڦྋࣁቘጱጱᔄ
ࣳӨ typeof ොဩӧݶጱฎ҅instanceof ොဩᥝݎᘏกᏟࣈᏟᦊԅᇙᔄࣳ
(3). ֵአconstructor༄ၥ constructorฎܻࣳӤጱં҅ݻ᭜ڍහ֕ฎ໑ഝֺ
ತંጱᶲଧ҅ᝑֺӤဌํֺંොဩ݄ܻ҅ࣳ᱾Ӥತ҅ࢩྌֺ҅
Ԟฎᚆֵአconstructorંጱ
jsහᕟ݄᯿҅ᚆአپᐿොဩሿҘ
(1).ֵአes6 setොဩ [...new Set(arr)] let arr = [1,2,3,4,3,2,3,4,6,7,6]; let unique = (arr)=> [...new
Set(arr)]; unique(arr);//[1, 2, 3, 4, 6, 7] (2).ڥአෛහᕟindexOfັತ indexOf() ොဩݢᬬࢧӻ
ጱزᔰࣁහᕟӾḒེڊሿጱ֖ᗝইຎဌํᬬࢧ-1 (3).for ᯿ሾ ᭗ᬦڣෙᒫԫሾ҅
݄᯿ጱහᕟӾฎވތํᧆزᔰ҅ইຎํᭅڊᒫԫሾ҅ইຎဌํj==result.lengthፘᒵ҅ᆐ
ݸଫጱزᔰႲےک๋ݸጱහᕟ᯾ᶎ