Add xterm itegration

* Move to TypeScript from legacy JavaScript
* Add support of xterm.js
* Hterm is still available for backward compatibility

js/src/hterm.ts

@@ -0,0 +1,93 @@
+import * as bare from "hterm";
+import * as bareLib from "htermLib";
+
+export class TermHterm {
+    elem: HTMLElement;
+
+    term: bare.Terminal;
+    io: bare.IO;
+
+    columns: number;
+    rows: number;
+
+    // to "show" the current message when removeMessage() is called
+    message: string;
+
+    constructor(elem: HTMLElement) {
+        this.elem = elem;
+        hterm.defaultStorage = new bareLib.Storage.Memory();
+        this.term = new bare.Terminal();
+        this.term.getPrefs().set("send-encoding", "raw");
+        this.term.decorate(this.elem);
+
+        this.io = this.term.io.push();
+        this.term.installKeyboard();
+    };
+
+    info(): { columns: number, rows: number } {
+        return { columns: this.columns, rows: this.rows };
+    };
+
+    output(data: string) {
+        if (this.term.io != null) {
+            this.term.io.writeUTF16(data);
+        }
+    };
+
+    showMessage(message: string, timeout: number) {
+        this.message = message;
+        if (timeout > 0) {
+            this.term.io.showOverlay(message, timeout);
+        } else {
+            this.term.io.showOverlay(message, null);
+        }
+    };
+
+    removeMessage(): void {
+        // there is no hideOverlay(), so show the same message with 0 sec
+        this.term.io.showOverlay(this.message, 0);
+    }
+
+    setWindowTitle(title: string) {
+        this.term.setWindowTitle(title);
+    };
+
+    setPreferences(value: object) {
+        Object.keys(value).forEach((key) => {
+            this.term.getPrefs().set(key, value[key]);
+        });
+    };
+
+    onInput(callback: (input: string) => void) {
+        this.io.onVTKeystroke = (data) => {
+            callback(data);
+        };
+        this.io.sendString = (data) => {
+            callback(data);
+        };
+    };
+
+    onResize(callback: (colmuns: number, rows: number) => void) {
+        this.io.onTerminalResize = (columns: number, rows: number) => {
+            this.columns = columns;
+            this.rows = rows;
+            callback(columns, rows);
+        };
+    };
+
+    deactivate(): void {
+        this.io.onVTKeystroke = null;
+        this.io.sendString = null
+        this.io.onTerminalResize = null;
+        this.term.uninstallKeyboard();
+    }
+
+    reset(): void {
+        this.removeMessage();
+        this.term.installKeyboard();
+    }
+
+    close(): void {
+        this.term.uninstallKeyboard();
+    }
+}