Javascript如何避免调用不存在的属性而导致报TypeError错？

问题var object = { ‘a’: [{ ‘b’: { ‘c’: 3 } }] }console.log(object.a[0].b.c.d)上述代码会返回方法一var object = { ‘a’: [{ ‘b’: { ‘c’: 3 } }] }console.log(object&&object.a)console.log(object&&object.a&&object.a[0])console.log(object&&object.a&&object.a[0]&&object.a[0].b)console.log(object&&object.a&&object.a[0]&&object.a[0].b&&object.a[0].b.c)console.log(object&&object.a&&object.a[0]&&object.a[0].b&&object.a[0].b.c&&object.a[0].b.c.d)方法二使用lodashvar object = { ‘a’: [{ ‘b’: { ‘c’: 3 } }] }console.log(.get(object, ‘a’))console.log(.get(object, ‘a[0]’))console.log(.get(object, ‘a[0].b’))console.log(.get(object, ‘a[0].b.c’))console.log(_.get(object, ‘a[0].b.c.d’))方法三var getProps = (p, o) => p.reduce((xs, x) => (xs && xs[x]) ? xs[x] : null, o)var object = { ‘a’: [{ ‘b’: { ‘c’: 3 } }] }console.log(getProps([‘a’], object))console.log(getProps([‘a’, ‘0’], object))console.log(getProps([‘a’, ‘0’, ‘b’], object))console.log(getProps([‘a’, ‘0’, ‘b’, ‘c’], object))console.log(getProps([‘a’, ‘0’, ‘b’, ‘c’, ’d’], object))方法四自判断链接,自判断链接还未纳入官方规范中，只处于第一阶段的实验特性。您需要在 babelrc 中添加 @ babel / plugin-proposal-optional-chaining 后方可使用它。var object = { ‘a’: [{ ‘b’: { ‘c’: 3 } }] }console.log(object?.a[0]?.b?.c?.d)参考链接[译] 优秀 JavaScript 开发人员应掌握的 9 个技巧