ES6 refactor of sql-string.js (#6080)

let, const,  arrow functions, exports

lib/sql-string.js

 'use strict';
 
 /* jshint -W110 */
-var dataTypes = require('./data-types')
-  , _ = require('lodash')
-  , SqlString = exports;
+const dataTypes = require('./data-types');
+const _ = require('lodash');
 
-SqlString.escapeId = function(val, forbidQualified) {
+function escapeId(val, forbidQualified) {
   if (forbidQualified) {
     return '`' + val.replace(/`/g, '``') + '`';
   }
   return '`' + val.replace(/`/g, '``').replace(/\./g, '`.`') + '`';
-};
+}
+exports.escapeId = escapeId;
 
-SqlString.escape = function(val, timeZone, dialect, format) {
-  var prependN = false;
+function escape(val, timeZone, dialect, format) {
+  let prependN = false;
   if (val === undefined || val === null) {
     return 'NULL';
   }
@@ -48,11 +48,11 @@ SqlString.escape = function(val, timeZone, dialect, format) {
   }
 
   if (Array.isArray(val)) {
-    var escape = _.partial(SqlString.escape, _, timeZone, dialect, format);
+    const partialEscape = _.partial(escape, _, timeZone, dialect, format);
     if (dialect === 'postgres' && !format) {
-      return dataTypes.ARRAY.prototype.stringify(val, {escape: escape});
+      return dataTypes.ARRAY.prototype.stringify(val, {escape});
     }
-    return val.map(escape);
+    return val.map(partialEscape);
   }
 
   if (!val.replace) {
@@ -64,7 +64,7 @@ SqlString.escape = function(val, timeZone, dialect, format) {
     // http://stackoverflow.com/q/603572/130598
     val = val.replace(/'/g, "''");
   } else {
-    val = val.replace(/[\0\n\r\b\t\\\'\"\x1a]/g, function(s) {
+    val = val.replace(/[\0\n\r\b\t\\\'\"\x1a]/g, s => {
       switch (s) {
         case '\0': return '\\0';
         case '\n': return '\\n';
@@ -77,30 +77,33 @@ SqlString.escape = function(val, timeZone, dialect, format) {
     });
   }
   return (prependN ? "N'" : "'") + val + "'";
-};
+}
+exports.escape = escape;
 
-SqlString.format = function(sql, values, timeZone, dialect) {
+function format(sql, values, timeZone, dialect) {
   values = [].concat(values);
 
-  return sql.replace(/\?/g, function(match) {
+  return sql.replace(/\?/g, match => {
     if (!values.length) {
       return match;
     }
 
-    return SqlString.escape(values.shift(), timeZone, dialect, true);
+    return escape(values.shift(), timeZone, dialect, true);
   });
-};
+}
+exports.format = format;
 
-SqlString.formatNamedParameters = function(sql, values, timeZone, dialect) {
-  return sql.replace(/\:+(?!\d)(\w+)/g, function(value, key) {
+function formatNamedParameters(sql, values, timeZone, dialect) {
+  return sql.replace(/\:+(?!\d)(\w+)/g, (value, key) => {
     if ('postgres' === dialect && '::' === value.slice(0, 2)) {
       return value;
     }
 
     if (values[key] !== undefined) {
-      return SqlString.escape(values[key], timeZone, dialect, true);
+      return escape(values[key], timeZone, dialect, true);
     } else {
       throw new Error('Named parameter "' + value + '" has no value in the given object.');
     }
   });
-};
+}
+exports.formatNamedParameters = formatNamedParameters;