Would you like to clone this notebook?
When you clone a notebook you are able to make changes without affecting the original notebook.
演示before-after-hook 的使用方法
const _ = require("lodash");
const Hook = require("before-after-hook");
let stepIndex = 0;
const getNextStep = ()=> {
stepIndex += 1;
return `<执行步骤${stepIndex}>`
}
/**
* Step1: 创建一个 Hook 的单一实例
*/
const hook = new Hook.Singular();
/**
* Step2: 模拟一个异步请求数据的函数, 返回一个 Promise对象
*/
const fetchData = (options =[]) => {
console.log(`${getNextStep()} - 进入fetchData 函数体`, options);
return new Promise((resolve, reject) => {
if (_.isArrayLike(options)) {
setTimeout(() => {
console.log(`${getNextStep()} - 获取到数据`)
resolve([1, 2, 3, 4]);
console.log(`${getNextStep()} - reslove`)
}, 3000);
} else if (_.isPlainObject(options)){
reject([0])
console.log(`${getNextStep()} - reject`)
} else {
throw new Error(`不兼容处理的值: ${options}`);
}
});
};
/**
* Step3: 创建一个与 fetchData 建立相互关系的 Hook 绑定
*/
const getDataWithHookable = (options) => {
return hook(fetchData, options)
.then((res) => {
console.log(`${getNextStep()} - then 执行异步请求有数据返回`);
console.log(`${getNextStep()} - 结果：`, res);
if (_.isUndefined(res)) {
throw new Error(-999)
}
})
.catch((err) => {
console.log(`${getNextStep()} - catch 执行异步请求发生异常`, err);
});
};
/**
* Step4：注册 before、error、after 的 hook
*/
hook.before(() => {
console.log(`${getNextStep()} - 调用 before hook`);
});
hook.error((err) => {
console.log(`${getNextStep()} - 调用 error hook`);
console.error(err);
});
hook.after(() => {
console.log(`${getNextStep()} - 调用 after hook`);
});
/**
* 生成器，针对数组
*/
function * asyncGeneratorForArray(array= []) {
let i = 0;
while (i < array.length) {
yield array[i++];
}
}
/**
* Step5: 正常调用 getDataWithHookable({});
* 会发现hook的部分，已经生效了
*/
async function main() {
// 根据输入不同的option值，处理结果是不一样的
const optionList = [[],{}, true];
for await (const option of asyncGeneratorForArray(optionList)) {
stepIndex = 0;
await getDataWithHookable(option);
console.log("-------------------");
}
}
main();
no comments
sign in to comment