answer-mini/wechat-app/static/vant/picker/index.js

import { VantComponent } from '../common/component';
import { pickerProps } from './shared';
VantComponent({
  classes: ['active-class', 'toolbar-class', 'column-class'],
  props: Object.assign(Object.assign({}, pickerProps), {
    valueKey: {
      type: String,
      value: 'text',
    },
    toolbarPosition: {
      type: String,
      value: 'top',
    },
    defaultIndex: {
      type: Number,
      value: 0,
    },
    columns: {
      type: Array,
      value: [],
      observer(columns = []) {
        this.simple = columns.length && !columns[0].values;
        this.children = this.selectAllComponents('.van-picker__column');
        if (Array.isArray(this.children) && this.children.length) {
          this.setColumns().catch(() => {});
        }
      },
    },
  }),
  beforeCreate() {
    this.children = [];
  },
  methods: {
    noop() {},
    setColumns() {
      const { data } = this;
      const columns = this.simple ? [{ values: data.columns }] : data.columns;
      const stack = columns.map((column, index) =>
        this.setColumnValues(index, column.values)
      );
      return Promise.all(stack);
    },
    emit(event) {
      const { type } = event.currentTarget.dataset;
      if (this.simple) {
        this.$emit(type, {
          value: this.getColumnValue(0),
          index: this.getColumnIndex(0),
        });
      } else {
        this.$emit(type, {
          value: this.getValues(),
          index: this.getIndexes(),
        });
      }
    },
    onChange(event) {
      if (this.simple) {
        this.$emit('change', {
          picker: this,
          value: this.getColumnValue(0),
          index: this.getColumnIndex(0),
        });
      } else {
        this.$emit('change', {
          picker: this,
          value: this.getValues(),
          index: event.currentTarget.dataset.index,
        });
      }
    },
    // get column instance by index
    getColumn(index) {
      return this.children[index];
    },
    // get column value by index
    getColumnValue(index) {
      const column = this.getColumn(index);
      return column && column.getValue();
    },
    // set column value by index
    setColumnValue(index, value) {
      const column = this.getColumn(index);
      if (column == null) {
        return Promise.reject(new Error('setColumnValue: 对应列不存在'));
      }
      return column.setValue(value);
    },
    // get column option index by column index
    getColumnIndex(columnIndex) {
      return (this.getColumn(columnIndex) || {}).data.currentIndex;
    },
    // set column option index by column index
    setColumnIndex(columnIndex, optionIndex) {
      const column = this.getColumn(columnIndex);
      if (column == null) {
        return Promise.reject(new Error('setColumnIndex: 对应列不存在'));
      }
      return column.setIndex(optionIndex);
    },
    // get options of column by index
    getColumnValues(index) {
      return (this.children[index] || {}).data.options;
    },
    // set options of column by index
    setColumnValues(index, options, needReset = true) {
      const column = this.children[index];
      if (column == null) {
        return Promise.reject(new Error('setColumnValues: 对应列不存在'));
      }
      const isSame =
        JSON.stringify(column.data.options) === JSON.stringify(options);
      if (isSame) {
        return Promise.resolve();
      }
      return column.set({ options }).then(() => {
        if (needReset) {
          column.setIndex(0);
        }
      });
    },
    // get values of all columns
    getValues() {
      return this.children.map((child) => child.getValue());
    },
    // set values of all columns
    setValues(values) {
      const stack = values.map((value, index) =>
        this.setColumnValue(index, value)
      );
      return Promise.all(stack);
    },
    // get indexes of all columns
    getIndexes() {
      return this.children.map((child) => child.data.currentIndex);
    },
    // set indexes of all columns
    setIndexes(indexes) {
      const stack = indexes.map((optionIndex, columnIndex) =>
        this.setColumnIndex(columnIndex, optionIndex)
      );
      return Promise.all(stack);
    },
  },
});