Question

I have a simple Vue script, learning Vue for the first time:

<!DOCTYPE html>
<html>
<head>
  <title>My first Vue app</title>
  <script src="https://cdn.jsdelivr.net/npm/vue"></script>
  <script src="https://cdn.jsdelivr.net/npm/axios@0.12.0/dist/axios.min.js"></script>
</head>
<body>
  <div id="watch-example">
      <p>
          Ask a yes/no question:
          <input v-model="question" type="text">
          <img v-bind:src="image">
      </p>
      <p>{{ answer }}</p>
  </div>
  <script>
    let watchExample = new Vue({

        // Root element of app
        el   : '#watch-example',

        // Properties keep track of
        data : {
            question : '',
            answer   : 'I cannot give you an answer until you ask a question!',
            image    : '',
        },
        watch : {
            question : function(newVal, oldVal) {
                const vm  = this;
                vm.answer = 'Waitinng for you to stop typing.';

                setTimeout(function() {
                    vm.getAnswer();
                }, 350);
            }
        },

        // App methods
        methods : {
            getAnswer: function() {
                const vm = this;

                if(!vm.question.includes('?')) {
                    vm.answer = 'Questions usually contain a question mark';
                    vm.image  = '';
                    return;
                }
                vm.answer = 'Thinking...';

                setTimeout(function() {
                    axios.get('https://yesno.wtf/api')
                        .then(function (response) {
                            vm.answer = response.data.answer;
                            vm.image  = response.data.image;
                        });
                }, 500);
            }
        }
    });
  </script>
</body>
</html>

I noticed that when I type a question, containing a question mark(?) too fast, it makes multiple requests, and I get multiple responses. It clears out images upon multiple returned responses and adds new ones. If I type a question slowly, only one response is returned.

console.log(response) shows the multiple responses in the console.

How can I make only one request to get one response to a question no matter the typing speed?

Answer 1

您可以在每次更改时重新启动计时器（即，停止当前计时器（如果有的话，然后再启动另一个计时器））。请注意，setTimeout()返回其关联的计时器ID，您可以将其传递给clearTimeout()以停止计时器。您的代码应类似于以下内容：

watch: {
    question : function(newVal, oldVal) {
        ...

        clearTimeout(this._timerId);
        this._timerId = setTimeout(function() {
            vm.getAnswer();
        }, 350);
    }
},

<!DOCTYPE html>
<html>
<head>
  <title>My first Vue app</title>
  <script src="https://cdn.jsdelivr.net/npm/vue"></script>
  <script src="https://cdn.jsdelivr.net/npm/axios@0.12.0/dist/axios.min.js"></script>
</head>
<body>
  <div id="watch-example">
      <p>
          Ask a yes/no question:
          <input v-model="question" type="text">
          <img v-bind:src="image">
      </p>
      <p>{{ answer }}</p>
  </div>
  <script>
    let watchExample = new Vue({

        // Root element of app
        el   : '#watch-example',

        // Properties keep track of
        data : {
            question : '',
            answer   : 'I cannot give you an answer until you ask a question!',
            image    : '',
        },
        watch : {
            question : function(newVal, oldVal) {
                const vm  = this;
                vm.answer = 'Waitinng for you to stop typing.';

                clearTimeout(this._timerId);
                this._timerId = setTimeout(function() {
                    vm.getAnswer();
                }, 350);
            }
        },

        // App methods
        methods : {
            getAnswer: function() {
                const vm = this;

                if(!vm.question.includes('?')) {
                    vm.answer = 'Questions usually contain a question mark';
                    vm.image  = '';
                    return;
                }
                vm.answer = 'Thinking...';

                setTimeout(function() {
                    axios.get('https://yesno.wtf/api')
                        .then(function (response) {
                            vm.answer = response.data.answer;
                            vm.image  = response.data.image;
                        });
                }, 500);
            }
        }
    });
  </script>
</body>
</html>

Answer 2

What you need here is debounce from lodash

A good example was given in the Vue documentation

Pay attention to this particular code, as an example:

created: function () {
    // _.debounce is a function provided by lodash to limit how
    // often a particularly expensive operation can be run.
    // In this case, we want to limit how often we access
    // yesno.wtf/api, waiting until the user has completely
    // finished typing before making the ajax request. To learn
    // more about the _.debounce function (and its cousin
    // _.throttle), visit: https://lodash.com/docs#debounce
    this.debouncedGetAnswer = _.debounce(this.getAnswer, 500)
  },

Answer 3

Currently your are just delaying your call by wrapping it in a setTimeout. I think you're trying to accomplish a debounce effect.

Lodash has this function but if you don't already use lodash and don't want to include it in your project you could easily write it yourself in a few lines of code.

Vuejs & Axios make multiple get requests

3 个答案: