104 lines
2.5 KiB
JavaScript
104 lines
2.5 KiB
JavaScript
import fs from 'fs';
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import { expect } from 'chai';
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const examples = {};
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function getAllPropertyNames(instance, seen = []) {
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if (!instance || seen.indexOf(instance) !== -1) {
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return [];
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}
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seen.push(instance); // we can purposely mutate seen, no reason to revisit nodes again
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let names = Object.getOwnPropertyNames(instance);
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if (instance.prototype) {
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names = names.concat(getAllPropertyNames(instance.prototype, seen));
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}
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if (instance.constructor) {
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names = names.concat(getAllPropertyNames(instance.constructor.prototype, seen));
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}
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return names;
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}
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class Interceptor {
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constructor(instance) {
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this._instance = instance;
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}
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intercept(callback) {
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this._callback = callback;
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this._attach();
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}
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_attach() {
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const original = this._original = [];
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const inst = this._instance;
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getAllPropertyNames(inst).forEach(method => {
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if (typeof inst[method] !== 'function') {
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return;
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}
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original.push(method);
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inst[method] = (...args) => this._catchCall(method, args);
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});
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}
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_detach() {
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this._original.forEach(key => {
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delete this._instance[key];
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});
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}
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_catchCall(method, args) {
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// detach before calling the underyling method to make sure we only get the first call
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this._detach();
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const retValue = this._instance[method].apply(this._instance, args);
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this._callback(method, args, retValue);
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return expect(retValue);
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}
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}
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/**
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* Magical function that can intercept method calls and stick them in a JSON
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* for the LaTeX renderer to pull.
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* @example
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* asDiagram('Vector.toUnitVector').it('should calculate unit vector', expectCall => {
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* expectCall(x).toUnitVector().to.vector.equal([0.6, 0.8]);
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* expectCall(new Vector([0, 0])).toUnitVector().to.vector.equal([0, 0]);
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* });
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* @param {String} name identifier of the diagram
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*/
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export function asDiagram(name) { // yes, this is very magic, but it makes our tests clean
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function expectCall(instance) {
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new Interceptor(instance).intercept((method, args, retValue) => {
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const record = { callee: instance, args, method, retValue };
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if (name in examples) {
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examples[name].push(record);
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} else {
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examples[name] = [record];
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}
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});
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return instance;
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}
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return {
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it(tname, handler) {
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if (handler === undefined) {
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[handler, tname] = [tname, name];
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}
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it(tname, () => handler(expectCall));
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}
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};
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}
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after(() =>
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fs.writeFileSync(
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`${__dirname}/../doc/gen/examples.json`,
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JSON.stringify(examples, null, 2)
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)
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);
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