判断是否为undefined或null
const isDef = (v) => {
return v !== undefined && v !== null
}
判断是否为Promise 函数
const isPromise = (val) => {
return (
val !== undefine &&
typeof val.then === 'function' &&
typeof val.catch === 'function'
)
}
判断是否为简单数据类型
const isPrimitive (value) => {
return (
typeof value === 'string' ||
typeof value === 'number' ||
typeof value === 'symbol' ||
typeof value === 'boolean'
)
}
严格检查复杂数据类型
const isPlainObject = (obj) => {
return Object.prototype.toString.call(obj) === '[object Object]'
}
const isRegExp = (v) => {
return Object.prototype.toString.call(v) === '[object RegExp]'
}
将驼峰字符串转成连接符 magicEightTall 转换成 magic-eight-tall
const hyphenateRE = /\B([A-Z])/g
const hyphenate = (str) => {
return str.replace(hyphenateRE, '-$1').toLowerCase()
}
将连接符转成驼峰字符串 magic-eight-tall 转换成 magicEightTall
const camelizeRE = /-(\w)/g
const camelize = (str) => {
return str.replace(camelizeRE, (_, c) => c ? c.toUpperCase() : '')
}
如果不想重复转换，可用以下方法调用转换函数
const cached = (fn) => {
const cache = Object.create(null)
console.log(cache);
return ((str) => {
const hit = cache[str]
return hit || (cache[str] = fn(str))
})
};
例
const camelize = cached((str) => {
return str.replace(camelizeRE, (_, c) => c ? c.toUpperCase() : '')
})