misc utils for browser and node

src/misc/utils.ts

@@ -0,0 +1,76 @@
+export class Utils {
+    static inited = false;
+    static isNode = false;
+    static isBrowser = true;
+
+    static init() {
+        if (Utils.inited) {
+            return;
+        }
+
+        Utils.inited = true;
+        Utils.isNode = typeof window === 'undefined';
+        Utils.isBrowser = !Utils.isNode;
+    }
+
+    static fromB64ToArray(str: string): Uint8Array {
+        if (Utils.isNode) {
+            return new Uint8Array(Buffer.from(str, 'base64'));
+        } else {
+            const binaryString = window.atob(str);
+            const bytes = new Uint8Array(binaryString.length);
+            for (let i = 0; i < binaryString.length; i++) {
+                bytes[i] = binaryString.charCodeAt(i);
+            }
+            return bytes;
+        }
+    }
+
+    static fromUtf8ToArray(str: string): Uint8Array {
+        if (Utils.isNode) {
+            return new Uint8Array(Buffer.from(str, 'utf8'));
+        } else {
+            const strUtf8 = unescape(encodeURIComponent(str));
+            const arr = new Uint8Array(strUtf8.length);
+            for (let i = 0; i < strUtf8.length; i++) {
+                arr[i] = strUtf8.charCodeAt(i);
+            }
+            return arr;
+        }
+    }
+
+    static fromBufferToB64(buffer: ArrayBuffer): string {
+        if (Utils.isNode) {
+            return new Buffer(buffer).toString('base64');
+        } else {
+            let binary = '';
+            const bytes = new Uint8Array(buffer);
+            for (let i = 0; i < bytes.byteLength; i++) {
+                binary += String.fromCharCode(bytes[i]);
+            }
+            return window.btoa(binary);
+        }
+    }
+
+    static fromBufferToUtf8(buffer: ArrayBuffer): string {
+        if (Utils.isNode) {
+            return new Buffer(buffer).toString('utf8');
+        } else {
+            const bytes = new Uint8Array(buffer);
+            const encodedString = String.fromCharCode.apply(null, bytes);
+            return decodeURIComponent(escape(encodedString));
+        }
+    }
+
+    // ref: https://stackoverflow.com/a/40031979/1090359
+    static fromBufferToHex(buffer: ArrayBuffer): string {
+        if (Utils.isNode) {
+            return new Buffer(buffer).toString('hex');
+        } else {
+            const bytes = new Uint8Array(buffer);
+            return Array.prototype.map.call(bytes, (x: number) => ('00' + x.toString(16)).slice(-2)).join('');
+        }
+    }
+}
+
+Utils.init();