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TA貢獻(xiàn)2012條經(jīng)驗(yàn) 獲得超12個(gè)贊
在 Javascript 中有多種訪問(wèn)對(duì)象的方法。
var myObj = {
variableOne: {
variableOneA: 'oneA',
variableOneB: 'oneB'
}
variableTwo: {
variableTwoA: 'twoA',
variableTwoB: 'twoB
}
variableThree: {
variableThreeA: 'threeA',
variableThreeB: 'threeB'
}
}
您可以使用“點(diǎn)”來(lái)訪問(wèn)對(duì)象的特定級(jí)別。
const valueVariableOneA = myObj.variableOne.variableOneA
console.log(valueVariableOneA) // output => "oneA"
您可以使用方括號(hào)代替點(diǎn)。當(dāng)您想用破折號(hào)創(chuàng)建對(duì)象的鍵時(shí),方括號(hào)很有用(例如:“cool-key”)
const valueVariableThreeB = myObj['variableThree']['variableThreeB']
console.log(valueVariableThreeB) // output => "threeB"
您還可以使用解構(gòu)來(lái)訪問(wèn)特定值
// Get value of variableTwoA key
const { variableTwoA } = myObj.variableTwo // first way
const { variableTwo : { variableTwoA } } = myObj // second way
console.log(variableTwoA) // output => "twoA"
現(xiàn)在要向嵌套對(duì)象添加鍵,您可以使用點(diǎn)或方括號(hào)方法。這是在第一級(jí)添加密鑰的方法。
myObj.variableFour = { variableFourA: 'fourA', variableFourB: 'fourB' }
myObj['variableFour'] = { variableFourA: 'fourA', variableFourB: 'fourB' }
// add key on nested object
myObj.variableOne.variableOneC = 'oneC'
myObj['variableOne']['variableOneC'] = 'oneC'
// you can mix both
myObj['variableOne'].variableOneC = 'oneC'
myObj.variableOne['variableOneC'] = 'oneC'
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