Pure Process
Primitives for business logic structuring
Install
npm install @yoomoney/pure-process
Promise chain exits
JavaScript
const {exit} = require('@yoomoney/pure-process');
const EXIT_CODE = {
needLogin: 'needLogin'
};
const getUser = async() => {
const {user, latency} = await fetchUser();
if (!user) {
exit(EXIT_CODE.needLogin, {latency});
}
return user;
};
const getPosts = async(user) => ({
posts: await fetchPosts(user.id)
});
const process = () => Promise.resolve()
.then(getUser)
.then(getPosts)
.then(...exit());
const output = await process();
if (output.exitCode === EXIT_CODE.needLogin) {
output.latency;
} else {
output.exitCode; // main (default)
output.posts;
}TypeScript
const {createExit} = require('@yoomoney/pure-process');
enum ExitCode {
NeedLogin = 'NEED_LOGIN',
NoPosts = 'NO_POSTS'
};
const exit = createExit<{
exitCode: ExitCode.NeedLogin;
latency: number;
} | {
exitCode: ExitCode.NoPosts
}>();
const getUser = async() => {
const {user, latency} = await fetchUser();
if (!user) {
exit(ExitCode.NeedLogin, {latency});
}
return user;
};
const getPosts = async(user: User) => ({
posts: await fetchPosts(user.id)
});
const process = () => Promise.resolve()
.then(getUser)
.then(getPosts)
.then(...exit());
const output = await process();
if (output.exitCode === ExitCode.NeedLogin) {
output.latency;
} else {
output.exitCode; // main (default)
output.posts;
}Sequential and parallel execution
const {pipeP, parallelMerge} = require('@yoomoney/pure-process');
const stepA = () => ({
resultA: 1
});
const stepB = ({resultA}) => ({
resultB: resultA + 1
});
const stepC = ({resultA}) => ({
resultC: resultA + 2
});
const process = () => Promise.resolve()
.then(stepA)
.then((data) => Promise.all([
stepB(data),
stepC(data)
]).then(([result1, result2]) => ({
...data,
...result1,
...result2
}))
);
// Equivalent
const process = pipeP(
stepA,
parallelMerge(
stepB,
stepC
)
);
expect(await process()).toEqual({
resultA: 1,
resultB: 2,
resultC: 3
});this argument of the created function is propagated to argument functions.
Sequences with exits
const process = pipeP(
stepA,
stepB,
exit.pipe
);Skip errors
const {skipErrors} = require('@yoomoney/pure-process');
const stepA = async(data) => ({
...data,
resultA: await fetchCritical()
});
const stepB = async(data) => ({
...data,
resultB: await fetchNonCritical()
});
const process = (data) => Promise.resolve(data)
.then(stepA)
.then(skipErrors(stepB));
await process({
// Optional
logError: console.log
});
