封装promise-API
var fs = require('fs')
function pReadFile(filePath) {
return new Promise(function (resolve, reject) {
fs.readFile(filePath, 'utf8', function (err, data) {
if (err) {
reject(err)
} else {
resolve(data)
}
})
})
}
pReadFile('./data/a.txt')
.then(function (data) {
console.log(data)
return pReadFile('./data/b.txt')
})
.then(function (data) {
console.log(data)
return pReadFile('./data/c.txt')
})
.then(function (data) {
console.log(data)
})