vue手写el-form组件

index.vue

<template>
  <div>
    <s-form :model="model" :rules="rules" ref="loginForm">
      <s-form-item label="用户名" prop="username">
        <s-input v-model="model.username"></s-input>
      </s-form-item>
      <s-form-item label="密码" prop="password">
        <s-input v-model="model.password" type="password"></s-input>
      </s-form-item>
      <s-form-item>
          <button @click="onLogin">登录</button>
      </s-form-item>
    </s-form>
    {{model}}
  </div>
</template>

<script>
import SInput from "./SInput.vue";
import SFormItem from "./SFormItem.vue";
import SForm from "./SForm.vue";

export default {
  components: {
    SInput,
    SFormItem,
    SForm
  },
  data() {
    return {
      model: {
        username: "tom",
        password: ""
      },
      rules: {
        username: [{ required: true, message: "用户名必填" }],
        password: [{ required: true, message: "密码必填" }]
      }
    };
  },
  methods: {
      onLogin() {
          this.$refs.loginForm.validate((isValid) => {
              if (isValid) {
                  alert('登录！！！')
              } else {
                  alert('有错！！')
              }
          })
      }
  },
};
</script>

SForm.vue

<template>
  <div>
    <slot></slot>
  </div>
</template>

<script>
export default {
  provide() {
    return {
      form: this // 传递Form实例给后代，比如FormItem用来校验
    };
  },
  props: {
    model: {
      type: Object,
      required: true
    },
    rules: {
      type: Object
    }
  },
  methods: {
    validate(cb) {
      // map结果是若干Promise数组
      const tasks = this.$children
        .filter(item => item.prop)
        .map(item => item.validate());
      //   所有任务必须全部成功才算校验通过
      Promise.all(tasks)
        .then(() => cb(true))
        .catch(() => cb(false));
    }
  }
};
</script>

<style lang="scss" scoped>
</style>

SFormItem.vue

<template>
  <div>
    <label v-if="label">{{label}}</label>
    <slot></slot>
    <!-- 校验信息 -->
    <p v-if="errorMessage">{{errorMessage}}</p>
  </div>
</template>

<script>
import Schema from "async-validator";

export default {
  data() {
    return {
      errorMessage: ""
    };
  },
  inject: ["form"],
  props: {
    label: {
      type: String,
      default: ""
    },
    prop: String
  },
  mounted() {
    // 监听校验事件、并执行监听
    this.$on("validate", () => {
      this.validate();
    });
  },
  methods: {
    validate() {
      // 执行组件校验
      // 1.获取校验规则
      const rules = this.form.rules[this.prop];

      // 2.获取数据
      const value = this.form.model[this.prop];

      // 3.执行校验
      const desc = {
        [this.prop]: rules
      };
      const schema = new Schema(desc);
      //   参数1是值,参数2是校验错误对象数组
    //   返回的Promise<boolean>
      return schema.validate({ [this.prop]: value }, errors => {
        if (errors) {
          // 有错
          this.errorMessage = errors[0].message;
        } else {
          // 没错，清除错误信息
          this.errorMessage = "";
        }
      });
    }
  }
};
</script>

<style lang="scss" scoped>
</style>

SInput.vue

<template>
    <div>
        <!-- 自定义组件要实现v-model必须实现:value, @input -->
        <!-- $attrs存储的是props之外的部分 -->
        <!-- {type:'password'} -->
        <input :value="value" @input="onInput" v-bind="$attrs">
    </div>
</template>

<script>
    export default {
        inheritAttrs: false, // 避免顶层容器继承属性
        props: {
            value: {
                type: String,
                default: ''
            }
        },
        methods: {
            onInput(e) {
                // 通知父组件数值变化
                this.$emit('input', e.target.value);

                // 通知FormItem校验
                this.$parent.$emit('validate');
            }
        },
    }
</script>

<style lang="scss" scoped>

</style>