SOURCE

const wsUri = 'ws://127.0.0.1:22003'
const matchServerUrl = 'http://localhost:8001/openapi/v1/match'
function FingerPrint() {
    let self = this
    this.websockt = null

    this.onOpen = function (evt) {
        message.innerHTML += '设备连接成功<br>'
        self.opendev()
    }
    this.onClose = function (evt) {
        alert('close')
    }
    this.onMessage = function (evt) {
        var jsondata = JSON.parse(evt.data);
        // 打开设备成功
        if (jsondata.function === 'open') {
            message.innerHTML += '设备已打开，可以开始识别<br>'
        }

        if (jsondata.datatype === "template") {
            let templateBase64 = jsondata.data.template
            self.match(templateBase64)
        }
    }
    this.onError = function (evt) {
        alert('error')
    }

    this.getinfo = function () {
        self.doSend("{\"module\":\"common\",\"function\":\"info\",\"msgid\":\"123456789\",\"parameter\":\"\"}");
    }

    this.opendev = function () {
        var str = "{\"module\":\"fingerprint\",\"function\":\"open\",\"msgid\":\"123456789\",\"parameter\":\"\"}"
        self.doSend(str);
    }

    this.match = function (templateBase64) {
        fetch(matchServerUrl, {
            "headers": {
                "accept": "application/json, text/plain, */*",
                "accept-language": "zh-CN,zh;q=0.9",
                "content-type": "application/json"
            },
            "body": JSON.stringify({ templateBase64 }),
            "method": "POST"
        }).then(r => {
            r.json().then(r => {
                console.log(r)
                alert(r.userId)
                if (r.userId == '') {
                    message.innerHTML += ('未识别的指纹<br>')
                    return
                }
                message.innerHTML += ('用户 ' + r.userId + ' 登录成功<br>')
            })
        })
    }

    this.init = function () {
        let websocket = new WebSocket(wsUri);

        websocket.onopen = function (evt) {
            self.onOpen(evt)
        };
        websocket.onclose = function (evt) {
            self.onClose(evt)
        };
        websocket.onmessage = function (evt) {
            self.onMessage(evt)
        };
        websocket.onerror = function (evt) {
            self.onError(evt)
        };

        self.websocket = websocket
    }

    this.doSend = function (message) {
        if (!this.websocket) {
            return
        }

        this.websocket.send(message);
    }

    return this

}

function test() {
    var a = FingerPrint()
    a.init()
}

<div>
    <button onclick="test()">指纹登录</button>
    <div id="message"></div>
</div>