feat: create escapeIdentifier utility

See brianc/node-postgres#1699

src/utilities/escapeIdentifier.js

@@ -0,0 +1,8 @@
+// @flow
+
+/**
+ * @see https://github.com/brianc/node-postgres/blob/6c840aabb09f8a2d640800953f6b884b6841384c/lib/client.js#L306-L322
+ */
+export default (identifier: string) => {
+  return '"' + identifier.replace(/"/g, '""') + '"';
+};

src/utilities/index.js

@@ -1,5 +1,6 @@
 // @flow
 
+export {default as escapeIdentifier} from './escapeIdentifier';
 export {default as mapTaggedTemplateLiteralInvocation} from './mapTaggedTemplateLiteralInvocation';
 export {default as normalizeAnonymousValuePlaceholders} from './normalizeAnonymousValuePlaceholders';
 export {default as normalizeNamedValuePlaceholders} from './normalizeNamedValuePlaceholders';

test/utilities/escapeIdentifier.js

@@ -0,0 +1,11 @@
+// @flow
+
+import test from 'ava';
+import {
+  escapeIdentifier
+} from '../../src/utilities';
+
+test('escapes a SQL identifier', (t) => {
+  t.true(escapeIdentifier('foo') === '"foo"');
+  t.true(escapeIdentifier('"foo"') === '"""foo"""');
+});