Extract common query and scan methods into a base object

clarkie · Apr 21, 2018 · 44440f4 · 44440f4
1 parent 78041c5
commit 44440f4
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Showing 3 changed files with 91 additions and 159 deletions.
diff --git a/lib/query-base.js b/lib/query-base.js
@@ -0,0 +1,85 @@
+'use strict';
+
+const _ = require('lodash');
+
+module.exports = {
+  limit(num) {
+    if (num <= 0) {
+      throw new Error('Limit must be greater than 0');
+    }
+
+    this.request.Limit = num;
+
+    return this;
+  },
+
+  filterExpression(expression) {
+    this.request.FilterExpression = expression;
+
+    return this;
+  },
+
+  expressionAttributeValues(data) {
+    this.request.ExpressionAttributeValues = data;
+
+    return this;
+  },
+
+  expressionAttributeNames(data) {
+    this.request.ExpressionAttributeNames = data;
+
+    return this;
+  },
+
+  projectionExpression(data) {
+    this.request.ProjectionExpression = data;
+
+    return this;
+  },
+
+  startKey(hashKey, rangeKey) {
+    this.request.ExclusiveStartKey = this.serializer.buildKey(hashKey, rangeKey, this.table.schema);
+
+    return this;
+  },
+
+  attributes(attrs) {
+    if (!_.isArray(attrs)) {
+      attrs = [attrs];
+    }
+
+    const expressionAttributeNames = _.reduce(attrs, (result, attr) => {
+      const path = `#${attr}`;
+      result[path] = attr;
+
+      return result;
+    }, {});
+
+    this.request.ProjectionExpression = _.keys(expressionAttributeNames).join(',');
+    this.request.ExpressionAttributeNames = _.merge({}, expressionAttributeNames, this.request.ExpressionAttributeNames);
+
+    return this;
+  },
+
+  select(value) {
+    this.request.Select = value;
+
+    return this;
+  },
+
+  returnConsumedCapacity(value) {
+    if (_.isUndefined(value)) {
+      value = 'TOTAL';
+    }
+
+    this.request.ReturnConsumedCapacity = value;
+
+    return this;
+  },
+
+  loadAll() {
+    this.options.loadAll = true;
+
+    return this;
+  },
+};
diff --git a/lib/query.js b/lib/query.js
@@ -2,6 +2,7 @@
 
 const _ = require('lodash');
 const expressions = require('./expressions');
+const queryBase = require('./query-base');
 const utils = require('./utils');
 
 const internals = {};
@@ -65,39 +66,8 @@ const Query = module.exports = function (hashKey, table, serializer) {
   this.request = {};
 };
 
-Query.prototype.limit = function (num) {
-  if (num <= 0) {
-    throw new Error('Limit must be greater than 0');
-  }
-
-  this.request.Limit = num;
-
-  return this;
-};
-
-Query.prototype.filterExpression = function (expression) {
-  this.request.FilterExpression = expression;
-
-  return this;
-};
-
-Query.prototype.expressionAttributeValues = function (data) {
-  this.request.ExpressionAttributeValues = data;
-
-  return this;
-};
-
-Query.prototype.expressionAttributeNames = function (data) {
-  this.request.ExpressionAttributeNames = data;
-
-  return this;
-};
-
-Query.prototype.projectionExpression = function (data) {
-  this.request.ProjectionExpression = data;
-
-  return this;
-};
+Query.prototype = Object.create(queryBase);
+Query.prototype.constructor = Query;
 
 Query.prototype.usingIndex = function (name) {
   this.request.IndexName = name;
@@ -152,30 +122,6 @@ Query.prototype.addFilterCondition = function (condition) {
   return this;
 };
 
-Query.prototype.startKey = function (hashKey, rangeKey) {
-  this.request.ExclusiveStartKey = this.serializer.buildKey(hashKey, rangeKey, this.table.schema);
-
-  return this;
-};
-
-Query.prototype.attributes = function (attrs) {
-  if (!_.isArray(attrs)) {
-    attrs = [attrs];
-  }
-
-  const expressionAttributeNames = _.reduce(attrs, (result, attr) => {
-    const path = `#${attr}`;
-    result[path] = attr;
-
-    return result;
-  }, {});
-
-  this.request.ProjectionExpression = _.keys(expressionAttributeNames).join(',');
-  this.request.ExpressionAttributeNames = _.merge({}, expressionAttributeNames, this.request.ExpressionAttributeNames);
-
-  return this;
-};
-
 Query.prototype.ascending = function () {
   this.request.ScanIndexForward = true;
 
@@ -188,28 +134,6 @@ Query.prototype.descending = function () {
   return this;
 };
 
-Query.prototype.select = function (value) {
-  this.request.Select = value;
-
-  return this;
-};
-
-Query.prototype.returnConsumedCapacity = function (value) {
-  if (_.isUndefined(value)) {
-    value = 'TOTAL';
-  }
-
-  this.request.ReturnConsumedCapacity = value;
-
-  return this;
-};
-
-Query.prototype.loadAll = function () {
-  this.options.loadAll = true;
-
-  return this;
-};
-
 Query.prototype.where = function (keyName) {
   return internals.keyCondition(keyName, this.table.schema, this);
 };

diff --git a/lib/scan.js b/lib/scan.js
@@ -2,6 +2,7 @@
 
 const _ = require('lodash');
 const expressions = require('./expressions');
+const queryBase = require('./query-base');
 const utils = require('./utils');
 
 const internals = {};
@@ -41,15 +42,8 @@ const Scan = module.exports = function (table, serializer) {
   this.request = {};
 };
 
-Scan.prototype.limit = function (num) {
-  if (num <= 0) {
-    throw new Error('Limit must be greater than 0');
-  }
-
-  this.request.Limit = num;
-
-  return this;
-};
+Scan.prototype = Object.create(queryBase);
+Scan.prototype.constructor = Scan;
 
 Scan.prototype.addFilterCondition = function (condition) {
   const expressionAttributeNames = _.merge({}, condition.attributeNames, this.request.ExpressionAttributeNames);
@@ -72,46 +66,6 @@ Scan.prototype.addFilterCondition = function (condition) {
   return this;
 };
 
-Scan.prototype.startKey = function (hashKey, rangeKey) {
-  this.request.ExclusiveStartKey = this.serializer.buildKey(hashKey, rangeKey, this.table.schema);
-
-  return this;
-};
-
-Scan.prototype.attributes = function (attrs) {
-  if (!_.isArray(attrs)) {
-    attrs = [attrs];
-  }
-
-  const expressionAttributeNames = _.reduce(attrs, (result, attr) => {
-    const path = `#${attr}`;
-    result[path] = attr;
-
-    return result;
-  }, {});
-
-  this.request.ProjectionExpression = _.keys(expressionAttributeNames).join(',');
-  this.request.ExpressionAttributeNames = _.merge({}, expressionAttributeNames, this.request.ExpressionAttributeNames);
-
-  return this;
-};
-
-Scan.prototype.select = function (value) {
-  this.request.Select = value;
-
-  return this;
-};
-
-Scan.prototype.returnConsumedCapacity = function (value) {
-  if (_.isUndefined(value)) {
-    value = 'TOTAL';
-  }
-
-  this.request.ReturnConsumedCapacity = value;
-
-  return this;
-};
-
 Scan.prototype.segments = function (segment, totalSegments) {
   this.request.Segment = segment;
   this.request.TotalSegments = totalSegments;
@@ -124,31 +78,6 @@ Scan.prototype.where = function (keyName) {
   return internals.keyCondition(keyName, this.table.schema, this);
 };
 
-
-Scan.prototype.filterExpression = function (expression) {
-  this.request.FilterExpression = expression;
-
-  return this;
-};
-
-Scan.prototype.expressionAttributeValues = function (data) {
-  this.request.ExpressionAttributeValues = data;
-
-  return this;
-};
-
-Scan.prototype.expressionAttributeNames = function (data) {
-  this.request.ExpressionAttributeNames = data;
-
-  return this;
-};
-
-Scan.prototype.projectionExpression = function (data) {
-  this.request.ProjectionExpression = data;
-
-  return this;
-};
-
 Scan.prototype.exec = function (callback) {
   const self = this;
 
@@ -159,12 +88,6 @@ Scan.prototype.exec = function (callback) {
   return utils.paginatedRequest(self, runScan, callback);
 };
 
-Scan.prototype.loadAll = function () {
-  this.options.loadAll = true;
-
-  return this;
-};
-
 Scan.prototype.buildRequest = function () {
   return _.merge({}, this.request, { TableName: this.table.tableName() });
 };