Merge pull request relayjs#63 from gaearon/smarter-search-match

Match search at word boundaries

Author: bvaughn

src/devtools/views/utils.js

@@ -6,7 +6,67 @@ import { meta } from '../../hydration';
 import type { HooksTree } from 'src/backend/types';
 
 export function createRegExp(string: string): RegExp {
-  return new RegExp(escapeStringRegExp(string), 'i');
+  // Allow /regex/ syntax with optional last /
+  if (string[0] === '/') {
+    // Cut off first slash
+    string = string.substring(1);
+    // Cut off last slash, but only if it's there
+    if (string[string.length - 1] === '/') {
+      string = string.substring(0, string.length - 1);
+    }
+    try {
+      return new RegExp(string, 'i');
+    } catch (err) {
+      // Bad regex. Make it not match anything.
+      // TODO: maybe warn in console?
+      return new RegExp('.^');
+    }
+  }
+
+  function isLetter(char: string) {
+    return char.toLowerCase() !== char.toUpperCase();
+  }
+
+  function matchAnyCase(char: string) {
+    if (!isLetter(char)) {
+      // Don't mess with special characters like [.
+      return char;
+    }
+    return '[' + char.toLowerCase() + char.toUpperCase() + ']';
+  }
+
+  // 'item' should match 'Item' and 'ListItem', but not 'InviteMom'.
+  // To do this, we'll slice off 'tem' and check first letter separately.
+  const escaped = escapeStringRegExp(string);
+  const firstChar = escaped[0];
+  let restRegex = '';
+  // For 'item' input, restRegex becomes '[tT][eE][mM]'
+  // We can't simply make it case-insensitive because first letter case matters.
+  for (let i = 1; i < escaped.length; i++) {
+    restRegex += matchAnyCase(escaped[i]);
+  }
+
+  if (!isLetter(firstChar)) {
+    // We can't put a non-character like [ in a group
+    // so we fall back to the simple case.
+    return new RegExp(firstChar + restRegex);
+  }
+
+  // Construct a smarter regex.
+  return new RegExp(
+    // For example:
+    // (^[iI]|I)[tT][eE][mM]
+    // Matches:
+    // 'Item'
+    // 'ListItem'
+    // but not 'InviteMom'
+    '(^' +
+      matchAnyCase(firstChar) +
+      '|' +
+      firstChar.toUpperCase() +
+      ')' +
+      restRegex
+  );
 }
 
 export function getMetaValueLabel(data: Object): string | null {