@ark7/router/flows.js

Ark7 Router layer framework.

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.TeePost = exports.Tee = exports._check = exports.Check = exports._when = exports.When = exports._if = exports.If = void 0;
const decorators_1 = require("./decorators");
const utils_1 = require("./utils");
/**
 * A IF middleware that helps a branch checking.  Usage:
 *
 *     @If(predictor, ifClause)
 *     - execute ifClause when predictor returns true.
 *     - execute next middleware when predictor returns false.
 *
 *     @If(predictor, ifClause, elseClause)
 *     - execute ifClause when predictor returns true.
 *     - execute elseClause when predictor returns false.
 *
 * @param predictor - Predict which clause to execute.
 * @param ifClause - Execute when predictor returns true.
 * @param elseClause - Execute when predictor returns false. By default, execute
 *                     else clause.
 */
function If(predictor, ifClause, elseClause) {
    return (0, decorators_1.Middleware)(_if(predictor, ifClause, elseClause));
}
exports.If = If;
function _if(predictor, ifClause, elseClause) {
    return async (ctx, next) => {
        const value = predictor(ctx);
        const boolValue = (0, utils_1.isPromise)(value) ? await value : value;
        if (boolValue) {
            await (0, utils_1.compose)(ifClause)(ctx, next);
        }
        else if (elseClause) {
            await (0, utils_1.compose)(elseClause)(ctx, next);
        }
        else {
            await next();
        }
    };
}
exports._if = _if;
/**
 * A WHEN middleware that helps a branch checking, next middleware will always
 * be executed regardless what predictor returns.
 *
 * @param predictor - Predict when the when clause will be executed.
 * @param whenClause - Execute when predictor returns true.
 */
function When(predictor, whenClause) {
    return (0, decorators_1.Middleware)(_when(predictor, whenClause));
}
exports.When = When;
function _when(predictor, whenClause) {
    return async (ctx, next) => {
        const value = predictor(ctx);
        const boolValue = (0, utils_1.isPromise)(value) ? await value : value;
        if (boolValue && whenClause) {
            await (0, utils_1.compose)(whenClause)(ctx, () => Promise.resolve({}));
        }
        await next();
    };
}
exports._when = _when;
/**
 * A CHECK middleware that helps determines if to execute next middleware.
 * Usage:
 *
 *   @Check((ctx: Router.IRouterContext) => ctx.isAuthenticated())
 *
 * @param predictor - Returns true to execute next middleware.
 */
function Check(predictor) {
    return (0, decorators_1.Middleware)(_check(predictor));
}
exports.Check = Check;
function _check(predictor) {
    return async (ctx, next) => {
        const value = predictor(ctx);
        const boolValue = (0, utils_1.isPromise)(value) ? await value : value;
        if (boolValue) {
            await next();
        }
    };
}
exports._check = _check;
/**
 * A Tee middleware that helps execute a side function.
 * Usage:
 *
 *   @Tee((ctx) => console.log(ctx.path))
 *
 * @param fn - The side function to execute.
 * @param opts.post - specifies run tee after returned.
 */
function Tee(fn, opts = {}) {
    async function process(ctx) {
        const value = fn(ctx, () => { });
        if ((0, utils_1.isPromise)(value)) {
            await value;
        }
    }
    return (0, decorators_1.Middleware)(async (ctx, next) => {
        if (!opts.post) {
            await process(ctx);
        }
        await next();
        if (opts.post) {
            await process(ctx);
        }
    });
}
exports.Tee = Tee;
function TeePost(fn) {
    return Tee(fn, { post: true });
}
exports.TeePost = TeePost;

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