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websql操作类封装

时间：2021-07-01 10:21:17 帮助过：5人阅读

　　上述代码存在的问题非常明显，由于websql操作都是异步操作，当我们为了获取到websql操作的结果之后再进行后续操作时，往往是通过回调函数来实现的，当回调一多的时候，回调地狱就出现了，为了解决回调地狱问题，我将通过Promise来改写，后续调用时，可以直接通过await和async来调用，或者直接通过Promise链式调用也是可以的。

　　现在我将通过ES6的语法重写之前的封装类，为了应用ES6中js面向对象的思想，我这里用到了class，最终代码如下：

技术图片 
import { browserVersions } from ‘@/utils/utils.js‘;
class SmpWebSql {
  constructor(options) {
    options = options || {};
    this.database = null;
    this.DateBaseName = options.DateBaseName || ‘RedDB‘;
    this.Version = options.Version || ‘1.0‘;
    this.Description = options.Description || ‘智维离线工单数据库‘;
    this.DataBaseSize = options.DataBaseSize || 2 * 1024 * 1024;
    this.init();
  }
  /**
   * 初始化数据库
   */
  init() {
    this.database = openDatabase(
      this.DateBaseName,
      this.Version,
      this.Description,
      this.DataBaseSize
    );
  }
  /**
   * 批量添加字段
   * @param {*} tableName 表名
   * @param {*} arr 更新的数据    [{key1：value1 , key2 : value2 ...},{key1：value1 , key2 : value2 ...}]
   * @param {*} index BLOG字段所在的索引位置
   * @param {*} isFirst 是否是第一次创建表
   */
  addBlob(tableName, arr, index, isFirst = true) {
    var _db = this.database;
    var _me = this;
    // eslint-disable-next-line promise/param-names
    return new Promise(function(resovle, reject) {
      if (arr == null) {
        return this;
      }
      var keyC = [];
      var keyI = [];
      var _key = ‘‘;
      arr = arr || [];
      if (arr && arr.constructor == Array) {
        for (var i in arr[0]) {
          keyC.push(i);
          keyI.push(i);
        }
        keyC[0] = keyC[0] + ‘ unique‘;
        _key = keyI.join(‘,‘);
        index = index == undefined ? 0 : index;
        keyC[index] = keyC[index] + ‘ BLOB‘;
        // eslint-disable-next-line promise/param-names

        _db.transaction(function(tx, result) {
          // var csql = ‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘;
          // console.log(‘csql:‘ + csql);
          if (isFirst == true) {
            tx.executeSql(
              ‘CREATE TABLE IF NOT EXISTS ‘ +
                tableName +
                ‘ (‘ +
                keyC.join(‘,‘) +
                ‘)‘
            );
          }
          // var sql = "";
          for (var s = 0, _len = arr.length; s < _len; s++) {
            var _value = _me.split(arr[s]);
            // sql += ‘INSERT INTO ‘ + tableName + ‘ (‘ + _key + ‘) VALUES (‘ + _value + ‘)‘;
            // console.log("sql:" + sql);
            tx.executeSql(
              ‘INSERT INTO ‘ +
                tableName +
                ‘ (‘ +
                _key +
                ‘) VALUES (‘ +
                _value +
                ‘)‘,
              [],
              function(tx, result) {
                resovle(result.rowsAffected);
                console.log(‘添加成功‘ + result.rowsAffected);
              },
              function(tx) {
                console.error(‘添加失败‘);
                // eslint-disable-next-line prefer-promise-reject-errors
                reject(false);
              }
            );
          }
          _key = keyI = keyC = null;
          resovle(arr.length);
        });
      }
    }).catch(error => {
      console.log(‘error :‘, error);
    });
  }
  /**
   * 批量添加字段
   * @param {*} tableName 表名
   * @param {*} arr 更新的数据    [{key1：value1 , key2 : value2 ...},{key1：value1 , key2 : value2 ...}]
   * @param {*} index BLOG字段所在的索引位置
   * @param {*} firstKey firstKey 第一个字段是否是主键（默认是）
   * @param {*} isFirst 是否是第一次创建表
   */
  patchAddBlob(tableName, arr, index, firstKey = true, isFirst = true) {
    var _db = this.database;
    var _me = this;
    // eslint-disable-next-line promise/param-names
    return new Promise(function(resovle, reject) {
      if (arr == null) {
        return this;
      }
      var keyC = [];
      var keyI = [];
      var _key = ‘‘;
      arr = arr || [];
      if (arr && arr.constructor == Array) {
        for (var i in arr[0]) {
          keyC.push(i);
          keyI.push(i);
        }
        if (firstKey) {
          keyC[0] = keyC[0] + ‘ unique‘;
        }
        _key = keyI.join(‘,‘);
        index = index == undefined ? 0 : index;
        keyC[index] = keyC[index] + ‘ text‘;
        // eslint-disable-next-line promise/param-names

        _db.transaction(function(tx, result) {
          // var csql = ‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘;
          // console.log(‘csql:‘ + csql);
          if (isFirst == true) {
            tx.executeSql(
              ‘CREATE TABLE IF NOT EXISTS ‘ +
                tableName +
                ‘ (‘ +
                keyC.join(‘,‘) +
                ‘)‘
            );
          }
          var sql = ‘‘;
          var _values = [];
          for (var s = 0, _len = arr.length; s < _len; s++) {
            _values.push(‘(‘ + _me.split(arr[s]) + ‘)‘);
          }
          sql =
            ‘INSERT INTO ‘ +
            tableName +
            ‘ (‘ +
            _key +
            ‘) VALUES ‘ +
            _values.join(‘,‘);
          // console.log(‘sql:‘ + sql);
          tx.executeSql(
            sql,
            [],
            function(tx, result) {
              resovle(result.rowsAffected);
              // console.log(‘添加成功‘+result.rowsAffected);
            },
            function(tx, error) {
              console.error(‘添加失败‘, tx, error);
              // eslint-disable-next-line prefer-promise-reject-errors
              reject(false);
            }
          );
          _key = keyI = keyC = null;
          resovle(arr.length);
        });
      }
    }).catch(error => {
      console.log(‘error :‘, error);
    });
  }
  /**
   * 批量添加字段 注 ： 数据里面的第一个key 为主键
   * @param {*} tableName 表名
   * @param {*} arr arr 更新的数据    [{key1：value1 , key2 : value2 ...},{key1：value1 , key2 : value2 ...}]
   * @param {*} firstKey firstKey 第一个字段是否是主键（默认是）
   */
  add(tableName, arr, firstKey = true) {
    var _me = this;
    var _db = this.database;
    // eslint-disable-next-line promise/param-names
    return new Promise(function(resovle, reject) {
      if (arr == null) {
        return this;
      }
      var keyC = [];
      var keyI = [];
      var _key = ‘‘;
      arr = arr || [];
      if (arr && arr.constructor == Array) {
        for (var i in arr[0]) {
          keyC.push(i);
          keyI.push(i);
        }
        if (firstKey) {
          keyC[0] = keyC[0] + ‘ unique‘;
        }
        _key = keyI.join(‘,‘);
        _db.transaction(function(tx) {
          // /var csql = ‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘;
          // console.log(‘csql:‘ + csql);
          tx.executeSql(
            ‘CREATE TABLE IF NOT EXISTS ‘ +
              tableName +
              ‘ (‘ +
              keyC.join(‘,‘) +
              ‘)‘
          );
          // var sql = "";
          for (var s = 0, _len = arr.length; s < _len; s++) {
            var _value = _me.split(arr[s]);
            // sql += ‘INSERT INTO ‘ + tableName + ‘ (‘ + _key + ‘) VALUES (‘ + _value + ‘)‘;
            // console.log("sql:" + sql);
            tx.executeSql(
              ‘INSERT INTO ‘ +
                tableName +
                ‘ (‘ +
                _key +
                ‘) VALUES (‘ +
                _value +
                ‘)‘,
              [],
              function(tx, result) {
                resovle(result.rowsAffected);
                // console.log(‘添加成功‘+result.rowsAffected);
              },
              function(tx, error) {
                console.error(‘添加失败‘, error);
                // eslint-disable-next-line prefer-promise-reject-errors
                reject(false);
              }
            );
          }
          _key = keyI = keyC = null;
          resovle(arr.length);
        });
      }
    }).catch(error => {
      console.log(‘error :‘, error);
    });
  }
  /**
   * 批量添加行记录 注 ： 数据里面的第一个key 为主键
   * @param {*} tableName 表名
   * @param {*} arr arr 更新的数据    [{key1：value1 , key2 : value2 ...},{key1：value1 , key2 : value2 ...}]
   * @param {*} firstKey firstKey 第一个字段是否是主键（默认是）
   */
  patchAdd(tableName, arr, firstKey = true) {
    var _me = this;
    var _db = this.database;
    // eslint-disable-next-line promise/param-names
    return new Promise(function(resovle, reject) {
      if (arr == null) {
        return this;
      }
      var keyC = [];
      var keyI = [];
      var _key = ‘‘;
      arr = arr || [];
      if (arr && arr.constructor == Array) {
        for (var i in arr[0]) {
          keyC.push(i);
          keyI.push(i);
        }
        if (firstKey) {
          keyC[0] = keyC[0] + ‘ unique‘;
        }
        _key = keyI.join(‘,‘);
        _db.transaction(function(tx) {
          // /var csql = ‘CREATE TABLE IF NOT EXISTS ‘ + tableName + ‘ (‘ + keyC.join(",") + ‘)‘;
          // console.log(‘csql:‘ + csql);
          tx.executeSql(
            ‘CREATE TABLE IF NOT EXISTS ‘ +
              tableName +
              ‘ (‘ +
              keyC.join(‘,‘) +
              ‘)‘
          );
          var sql = ‘‘;
          var _values = [];
          for (var s = 0, _len = arr.length; s < _len; s++) {
            _values.push(‘(‘ + _me.split(arr[s]) + ‘)‘);
          }
          sql =
            ‘INSERT INTO ‘ +
            tableName +
            ‘ (‘ +
            _key +
            ‘) VALUES ‘ +
            _values.join(‘,‘);
          console.log(‘sql:‘ + sql);

          tx.executeSql(
            sql,
            [],
            function(tx, result) {
              resovle(result.rowsAffected);
              // console.log(‘添加成功‘+result.rowsAffected);
            },
            function(tx, error) {
              console.error(‘添加失败‘);
              // eslint-disable-next-line prefer-promise-reject-errors
              reject(false);
            }
          );
          _key = keyI = keyC = null;
          resovle(arr.length);
        });
      }
    }).catch(error => {
      console.log(‘error :‘, error);
    });
  }

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websql操作类封装

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