Initialization Control

The following static methods and properties help to set up the runtime environment for the library.

• Initialization Control
  • engineResourcePath
  • loadWasm
  • isWasmLoaded
  • version
  • detectEnvironment
  • onWarning

engineResourcePath

Specifies the path to find the engine(s). The property needs to be set before loadWasm. If not specified, the library will try to find the engine in the same location as the main JavaScript file (dbr.js).

static engineResourcePath: string

Code Snippet

Dynamsoft.DBR.BarcodeReader.engineResourcePath = "https://cdn.jsdelivr.net/npm/dynamsoft-javascript-barcode@9.6.40/dist/";
await Dynamsoft.DBR.BarcodeReader.loadWasm();

loadWasm

Downloads and compiles the engine to get it loaded/ready for a BarcodeReader or BarcodeScanner instance to be created. You can call this API to silently set the operating environment of the library as soon as the page is loaded, avoiding unnecessary waiting time when using the library later.

If this API is not called beforehand, it will be called automatically when creating an instance of BarcodeReader or BarcodeScanner.

static loadWasm(): Promise<void>

Return Value

A promise that resolves when the operation succeeds.

Code Snippet

window.addEventListener('DOMContentLoaded', (event) => {
    Dynamsoft.DBR.BarcodeReader.loadWasm();
});

** Tips and Tricks **

• How to get rid of the delay when opening the camera?

isWasmLoaded

Returns whether the engine is loaded/ready.

static isWasmLoaded(): boolean

version

Returns the version of the library including the detailed version numbers of the engine and the main JavaScript code.

The engine version is only valid after loadWasm has been called.

readonly static version: string

Code Snippet

console.log(Dynamsoft.DBR.BarcodeReader.version);
// loading...(JS 8.8.3.20211011)
await Dynamsoft.DBR.BarcodeReader.loadWasm();
console.log("When loaded..." + Dynamsoft.DBR.BarcodeReader.version);
// 8.8.0.10403(JS 8.8.3.20211011)

detectEnvironment

Detects the current running environment and returns a report.

static detectEnvironment(): Promise<any>

Return value

A promise resolving to an object which contains some information of the current running environment.

Code Snippet

console.log(await Dynamsoft.DBR.BarcodeReader.detectEnvironment());
// {"wasm":true, "worker":true, "getUserMedia":true, "camera":true, 
// "browser":"Chrome", "version":90, "OS":"Windows"}

onWarning

A callback which is triggered when the running environment is not ideal. In this version, it may get triggered in two scenarios:

1. If the page is opened from the disk
2. The page is hosted in a HTTP site without SSL

In both cases, the following warning is returned:

{
    id: 2,
    message: "Not connected via SSL (HTTPS), the SDK may not work correctly."
}

Code Snippet

Dynamsoft.DBR.BarcodeScanner.onWarning = warning => console.log(warning.message);

See Also

Warning