https://www.digifactory.fr/admin/inc/js/mod/app/DependencyLoader.js

1export class DependencyLoader {
2    loadModules(modules) {
3        return this.__load(modules, '__loadModule');
4    }
5
6    loadScripts(scripts) {
7        return this.__load(scripts, '__loadScript');
8    }
9
10    loadModularScripts(scripts) {
11        return this.__load(scripts, '__loadModularScript');
12    }
13
14    loadStyles(styles) {
15        return this.__load(styles, '__loadStyle');
16    }
17
18    __load(items, loaderFunctionName) {
19        if (typeof items == 'string') items = [items];
20
21        let promises = [];
22
23        for (let item of items) {
24            if (typeof item == 'string') {
25                // Chargement de script simple
26                promises.push(this[loaderFunctionName](item));
27            } else {
28                // Chargement de script(s) sur plusieurs niveaux
29                let toLoadPromise = new Promise((resolve, reject) => {
30                    this['__load'](item.load, loaderFunctionName).then((mainOutput) => {
31                        if ('then' in item) {
32                            this['__load'](item.then, loaderFunctionName).then((thenOutputs) => {
33                                resolve(this.__mergeOutputs([].concat(mainOutput, thenOutputs), loaderFunctionName));
34                            });
35                        } else {
36                            resolve(mainOutput);
37                        }
38                    })
39                });
40
41                promises.push(toLoadPromise);
42            }
43        }
44
45        return new Promise((resolve, reject) => {
46			Promise.all(promises)
47				.then((outputs) => {
48					resolve(this.__mergeOutputs(outputs, loaderFunctionName));
49				})
50				.catch((e) => reject(e));
51		});
52    }
53
54	__mergeOutputs(outputs, loaderFunctionName) {
55		if (loaderFunctionName == '__loadModularScript') {
56			let outputData = {};
57			for (let output of outputs) {
58				if (typeof output != 'object') continue;
59
60				for (let [className, exportClass] of Object.entries(output)) {
61					outputData[className] = exportClass;
62				}
63			}
64			return outputData;
65		} else {
66			return outputs;
67		}
68	}
69
70    __loadScript(url) {
71        let head = document.getElementsByTagName('head')[0];
72        if (!head) throw "Document must have a HEAD tag to dynamically load scripts";
73
74        let script = this.__getDocumentScriptFromUrl(url);
75        if (script) {
76            // Script already added
77            if ('__loader' in script) {
78                // Added from DependencyLoader
79                return script.__loader.promise;
80            } else {
81                return Promise.resolve(script);// TODO: Found a solution to know if an error occurred
82            }
83        } else {
84            let loader = {promise: null};
85
86            loader.promise = new Promise((resolve, reject) => {
87                script = document.createElement('script');
88                script.__loader = loader;
89                script.src = url;
90                script.async = true;
91                script.type = 'text/javascript';
92
93                script.onload = function () {
94                    resolve(script);
95                };
96                script.onerror = function () {
97                    reject();
98                };
99
100                head.appendChild(script);
101            });
102
103            return loader.promise;
104        }
105    }
106
107
108    __loadModularScript(url) {
109		return new Promise((resolve, reject) => {
110			import(url).then((module) => {
111				resolve(module);
112			});
113		});
114    }
115
116    __loadModule(moduleId) {
117        return window.appModules.loadModule(moduleId);
118    }
119
120    __loadStyle(url) {
121        let head = document.getElementsByTagName('head')[0];
122        if (!head) throw "Document must have a HEAD tag to dynamically load stylesheets";
123
124        let styleSheet = this.__getDocumentStyleSheetFromUrl(url);
125        if (styleSheet) {
126            // Script already added
127            if ('__loader' in styleSheet) {
128                // Added from DependencyLoader
129                return styleSheet.__loader.promise;
130            } else {
131                return Promise.resolve(styleSheet); // TODO: Found a solution to know if an error occurred
132            }
133        } else {
134            let loader = {promise: null};
135            loader.promise = new Promise((resolve, reject) => {
136                styleSheet = document.createElement('link');
137                styleSheet.__loader = loader;
138                styleSheet.href = url;
139                styleSheet.rel = 'stylesheet';
140                styleSheet.type = 'text/css';
141
142                styleSheet.onload = function () {
143                    resolve(styleSheet);
144                };
145                styleSheet.onerror = function () {
146                    reject();
147                };
148
149                head.appendChild(styleSheet);
150            });
151
152            return loader.promise;
153        }
154    }
155
156    __getDocumentScriptFromUrl(url) {
157        if (!url.match(/^https?:/)) {
158            if (!url.match(/^\//)) url = document.location.pathname.replace(/\/$/)+'/'+url;
159
160            url = document.location.protocol+'//'+document.location.host+url;
161        }
162
163        for (let script of document.scripts) {
164            if (script.src == url) return script;
165        }
166
167        return null;
168    }
169
170    __getDocumentStyleSheetFromUrl(url) {
171        if (!url.match(/^https?:/)) {
172            if (!url.match(/^\//)) url = document.location.pathname.replace(/\/$/)+'/'+url;
173
174            url = document.location.protocol+'//'+document.location.host+url;
175        }
176
177        for (let styleSheet of document.styleSheets) {
178            if (styleSheet.href == url) return styleSheet;
179        }
180
181        return null;
182    }
183}
184
185window.dependencyLoader = new DependencyLoader();