2026-01-22 21:21:56 +05:30

510 lines
14 KiB
JavaScript

'use strict';
/**
* Create a new instance
*/
function Kareem() {
this._pres = new Map();
this._posts = new Map();
}
Kareem.skipWrappedFunction = function skipWrappedFunction() {
if (!(this instanceof Kareem.skipWrappedFunction)) {
return new Kareem.skipWrappedFunction(...arguments);
}
this.args = [...arguments];
};
Kareem.overwriteResult = function overwriteResult() {
if (!(this instanceof Kareem.overwriteResult)) {
return new Kareem.overwriteResult(...arguments);
}
this.args = [...arguments];
};
Kareem.overwriteArguments = function overwriteArguments() {
if (!(this instanceof Kareem.overwriteArguments)) {
return new Kareem.overwriteArguments(...arguments);
}
this.args = [...arguments];
};
/**
* Execute all "pre" hooks for "name"
* @param {String} name The hook name to execute
* @param {*} context Overwrite the "this" for the hook
* @param {Array} args arguments passed to the pre hooks
* @returns {Array} The potentially modified arguments
*/
Kareem.prototype.execPre = async function execPre(name, context, args) {
const pres = this._pres.get(name) || [];
const numPres = pres.length;
let $args = args;
let skipWrappedFunction = null;
if (!numPres) {
return $args;
}
for (const pre of pres) {
const args = [];
const _args = [null].concat($args);
for (let i = 1; i < _args.length; ++i) {
if (i === _args.length - 1 && typeof _args[i] === 'function') {
continue; // skip callbacks to avoid accidentally calling the callback from a hook
}
args.push(_args[i]);
}
try {
const maybePromiseLike = pre.fn.apply(context, args);
if (isPromiseLike(maybePromiseLike)) {
const result = await maybePromiseLike;
if (result instanceof Kareem.overwriteArguments) {
$args = result.args;
}
} else if (maybePromiseLike instanceof Kareem.overwriteArguments) {
$args = maybePromiseLike.args;
}
} catch (error) {
if (error instanceof Kareem.skipWrappedFunction) {
skipWrappedFunction = error;
continue;
}
if (error instanceof Kareem.overwriteArguments) {
$args = error.args;
continue;
}
throw error;
}
}
if (skipWrappedFunction) {
throw skipWrappedFunction;
}
return $args;
};
/**
* Execute all "pre" hooks for "name" synchronously
* @param {String} name The hook name to execute
* @param {*} context Overwrite the "this" for the hook
* @param {Array} [args] Apply custom arguments to the hook
* @returns {Array} The potentially modified arguments
*/
Kareem.prototype.execPreSync = function(name, context, args) {
const pres = this._pres.get(name) || [];
const numPres = pres.length;
let $args = args || [];
for (let i = 0; i < numPres; ++i) {
const result = pres[i].fn.apply(context, $args);
if (result instanceof Kareem.overwriteArguments) {
$args = result.args;
}
}
return $args;
};
/**
* Execute all "post" hooks for "name"
* @param {String} name The hook name to execute
* @param {*} context Overwrite the "this" for the hook
* @param {Array} args Apply custom arguments to the hook
* @param {*} options Optional options or directly the callback
* @returns {void}
*/
Kareem.prototype.execPost = async function execPost(name, context, args, options) {
const posts = this._posts.get(name) || [];
const numPosts = posts.length;
let firstError = null;
if (options && options.error) {
firstError = options.error;
}
if (!numPosts) {
if (firstError != null) {
throw firstError;
}
return args;
}
for (const currentPost of posts) {
const post = currentPost.fn;
let numArgs = 0;
const newArgs = [];
const argLength = args.length;
for (let i = 0; i < argLength; ++i) {
if (!args[i] || !args[i]._kareemIgnore) {
numArgs += 1;
newArgs.push(args[i]);
}
}
// If numCallbackParams set, fill in the rest with null to enforce consistent number of args
if (options?.numCallbackParams != null) {
numArgs = options.numCallbackParams;
for (let i = newArgs.length; i < numArgs; ++i) {
newArgs.push(null);
}
}
let resolve;
let reject;
const cbPromise = new Promise((_resolve, _reject) => {
resolve = _resolve;
reject = _reject;
});
newArgs.push(function nextCallback(err) {
if (err) {
reject(err);
} else {
resolve();
}
});
if (firstError) {
if (isErrorHandlingMiddleware(currentPost, numArgs)) {
try {
const res = post.apply(context, [firstError].concat(newArgs));
if (isPromiseLike(res)) {
await res;
} else if (post.length === numArgs + 2) {
// `numArgs + 2` because we added the error and the callback
await cbPromise;
}
} catch (error) {
if (error instanceof Kareem.overwriteResult) {
args = error.args;
continue;
}
firstError = error;
}
} else {
continue;
}
} else {
if (isErrorHandlingMiddleware(currentPost, numArgs)) {
// Skip error handlers if no error
continue;
} else {
let res = null;
try {
res = post.apply(context, newArgs);
if (isPromiseLike(res)) {
res = await res;
} else if (post.length === numArgs + 1) {
// If post function takes a callback, wait for the post function to call the callback
res = await cbPromise;
}
} catch (error) {
if (error instanceof Kareem.overwriteResult) {
args = error.args;
continue;
}
firstError = error;
continue;
}
if (res instanceof Kareem.overwriteResult) {
args = res.args;
continue;
}
}
}
}
if (firstError != null) {
throw firstError;
}
return args;
};
/**
* Execute all "post" hooks for "name" synchronously
* @param {String} name The hook name to execute
* @param {*} context Overwrite the "this" for the hook
* @param {Array} args Apply custom arguments to the hook
* @returns {Array} The used arguments
*/
Kareem.prototype.execPostSync = function(name, context, args) {
const posts = this._posts.get(name) || [];
const numPosts = posts.length;
for (let i = 0; i < numPosts; ++i) {
const res = posts[i].fn.apply(context, args || []);
if (res instanceof Kareem.overwriteResult) {
args = res.args;
}
}
return args;
};
/**
* Create a synchronous wrapper for "fn"
* @param {String} name The name of the hook
* @param {Function} fn The function to wrap
* @returns {Function} The wrapped function
*/
Kareem.prototype.createWrapperSync = function(name, fn) {
const _this = this;
return function syncWrapper() {
const modifiedArgs = _this.execPreSync(name, this, Array.from(arguments));
const toReturn = fn.apply(this, modifiedArgs);
const result = _this.execPostSync(name, this, [toReturn]);
return result[0];
};
};
/**
* Executes pre hooks, followed by the wrapped function, followed by post hooks.
* @param {String} name The name of the hook
* @param {Function} fn The function for the hook
* @param {*} context Overwrite the "this" for the hook
* @param {Array} args Apply custom arguments to the hook
* @param {Object} options Additional options for the hook
* @returns {void}
*/
Kareem.prototype.wrap = async function wrap(name, fn, context, args, options) {
let ret;
let skipWrappedFunction = false;
let modifiedArgs = args;
try {
modifiedArgs = await this.execPre(name, context, args);
} catch (error) {
if (error instanceof Kareem.skipWrappedFunction) {
ret = error.args;
skipWrappedFunction = true;
} else {
await this.execPost(name, context, args, { ...options, error });
}
}
if (!skipWrappedFunction) {
ret = await fn.apply(context, modifiedArgs);
}
ret = await this.execPost(name, context, [ret], options);
return ret[0];
};
/**
* Filter current instance for something specific and return the filtered clone
* @param {Function} fn The filter function
* @returns {Kareem} The cloned and filtered instance
*/
Kareem.prototype.filter = function(fn) {
const clone = this.clone();
const pres = Array.from(clone._pres.keys());
for (const name of pres) {
const hooks = this._pres.get(name).
map(h => Object.assign({}, h, { name: name })).
filter(fn);
if (hooks.length === 0) {
clone._pres.delete(name);
continue;
}
clone._pres.set(name, hooks);
}
const posts = Array.from(clone._posts.keys());
for (const name of posts) {
const hooks = this._posts.get(name).
map(h => Object.assign({}, h, { name: name })).
filter(fn);
if (hooks.length === 0) {
clone._posts.delete(name);
continue;
}
clone._posts.set(name, hooks);
}
return clone;
};
/**
* Check for a "name" to exist either in pre or post hooks
* @param {String} name The name of the hook
* @returns {Boolean} "true" if found, "false" otherwise
*/
Kareem.prototype.hasHooks = function(name) {
return this._pres.has(name) || this._posts.has(name);
};
/**
* Create a Wrapper for "fn" on "name" and return the wrapped function
* @param {String} name The name of the hook
* @param {Function} fn The function to wrap
* @param {*} context Overwrite the "this" for the hook
* @param {Object} [options]
* @returns {Function} The wrapped function
*/
Kareem.prototype.createWrapper = function(name, fn, context, options) {
const _this = this;
if (!this.hasHooks(name)) {
// Fast path: if there's no hooks for this function, just return the function
return fn;
}
return function kareemWrappedFunction() {
const _context = context || this;
return _this.wrap(name, fn, _context, Array.from(arguments), options);
};
};
/**
* Register a new hook for "pre"
* @param {String} name The name of the hook
* @param {Object} [options]
* @param {Function} fn The function to register for "name"
* @param {never} error Unused
* @param {Boolean} [unshift] Wheter to "push" or to "unshift" the new hook
* @returns {Kareem}
*/
Kareem.prototype.pre = function(name, options, fn, error, unshift) {
if (typeof options === 'function') {
fn = options;
options = {};
} else if (options == null) {
options = {};
}
const pres = this._pres.get(name) || [];
this._pres.set(name, pres);
if (typeof fn !== 'function') {
throw new Error('pre() requires a function, got "' + typeof fn + '"');
}
if (unshift) {
pres.unshift(Object.assign({}, options, { fn: fn }));
} else {
pres.push(Object.assign({}, options, { fn: fn }));
}
return this;
};
/**
* Register a new hook for "post"
* @param {String} name The name of the hook
* @param {Object} [options]
* @param {Boolean} [options.errorHandler] Whether this is an error handler
* @param {Function} fn The function to register for "name"
* @param {Boolean} [unshift] Wheter to "push" or to "unshift" the new hook
* @returns {Kareem}
*/
Kareem.prototype.post = function(name, options, fn, unshift) {
const posts = this._posts.get(name) || [];
if (typeof options === 'function') {
unshift = !!fn;
fn = options;
options = {};
}
if (typeof fn !== 'function') {
throw new Error('post() requires a function, got "' + typeof fn + '"');
}
if (unshift) {
posts.unshift(Object.assign({}, options, { fn: fn }));
} else {
posts.push(Object.assign({}, options, { fn: fn }));
}
this._posts.set(name, posts);
return this;
};
/**
* Register a new error handler for "name"
* @param {String} name The name of the hook
* @param {Object} [options]
* @param {Function} fn The function to register for "name"
* @param {Boolean} [unshift] Wheter to "push" or to "unshift" the new hook
* @returns {Kareem}
*/
Kareem.prototype.postError = function postError(name, options, fn, unshift) {
if (typeof options === 'function') {
unshift = !!fn;
fn = options;
options = {};
}
return this.post(name, { ...options, errorHandler: true }, fn, unshift);
};
/**
* Clone the current instance
* @returns {Kareem} The cloned instance
*/
Kareem.prototype.clone = function() {
const n = new Kareem();
for (const key of this._pres.keys()) {
const clone = this._pres.get(key).slice();
n._pres.set(key, clone);
}
for (const key of this._posts.keys()) {
n._posts.set(key, this._posts.get(key).slice());
}
return n;
};
/**
* Merge "other" into self or "clone"
* @param {Kareem} other The instance to merge with
* @param {Kareem} [clone] The instance to merge onto (if not defined, using "this")
* @returns {Kareem} The merged instance
*/
Kareem.prototype.merge = function(other, clone) {
clone = arguments.length === 1 ? true : clone;
const ret = clone ? this.clone() : this;
for (const key of other._pres.keys()) {
const sourcePres = ret._pres.get(key) || [];
const deduplicated = other._pres.get(key).
// Deduplicate based on `fn`
filter(p => sourcePres.map(_p => _p.fn).indexOf(p.fn) === -1);
const combined = sourcePres.concat(deduplicated);
ret._pres.set(key, combined);
}
for (const key of other._posts.keys()) {
const sourcePosts = ret._posts.get(key) || [];
const deduplicated = other._posts.get(key).
filter(p => sourcePosts.indexOf(p) === -1);
ret._posts.set(key, sourcePosts.concat(deduplicated));
}
return ret;
};
function isPromiseLike(v) {
return (typeof v === 'object' && v !== null && typeof v.then === 'function');
}
function isErrorHandlingMiddleware(post, numArgs) {
if (post.errorHandler) {
return true;
}
return post.fn.length === numArgs + 2;
}
module.exports = Kareem;