repl: add support for custom completions

Allow user code to override the default `complete()` function from
`readline.Interface`. See:
https://nodejs.org/api/readline.html#readline_use_of_the_completer_function

Ref: https://github.com/nodejs/node-v0.x-archive/pull/8484

PR-URL: https://github.com/nodejs/node/pull/7527
Reviewed-By: James M Snell <jasnell@gmail.com>
Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Lance Ball <lball@redhat.com>

1 files changed, 66 insertions, 1 deletions

diff --git a/test/parallel/test-repl-tab-complete.js b/test/parallel/test-repl-tab-complete.js
index 3d32d8e0ce..73a3fd148b 100644
--- a/test/parallel/test-repl-tab-complete.js
+++ b/test/parallel/test-repl-tab-complete.js
@@ -32,7 +32,7 @@ testMe.complete('console.lo', common.mustCall(function(error, data) {
   assert.deepStrictEqual(data, [['console.log'], 'console.lo']);
 }));
 
-// Tab Complete will return globaly scoped variables
+// Tab Complete will return globally scoped variables
 putIn.run(['};']);
 testMe.complete('inner.o', common.mustCall(function(error, data) {
   assert.deepStrictEqual(data, works);
@@ -283,3 +283,68 @@ if (typeof Intl === 'object') {
 testNonGlobal.complete('I', common.mustCall((error, data) => {
   assert.deepStrictEqual(data, builtins);
 }));
+
+// To test custom completer function.
+// Sync mode.
+const customCompletions = 'aaa aa1 aa2 bbb bb1 bb2 bb3 ccc ddd eee'.split(' ');
+const testCustomCompleterSyncMode = repl.start({
+  prompt: '',
+  input: putIn,
+  output: putIn,
+  completer: function completerSyncMode(line) {
+    const hits = customCompletions.filter((c) => {
+      return c.indexOf(line) === 0;
+    });
+    // Show all completions if none found.
+    return [hits.length ? hits : customCompletions, line];
+  }
+});
+
+// On empty line should output all the custom completions
+// without complete anything.
+testCustomCompleterSyncMode.complete('', common.mustCall((error, data) => {
+  assert.deepStrictEqual(data, [
+    customCompletions,
+    ''
+  ]);
+}));
+
+// On `a` should output `aaa aa1 aa2` and complete until `aa`.
+testCustomCompleterSyncMode.complete('a', common.mustCall((error, data) => {
+  assert.deepStrictEqual(data, [
+    'aaa aa1 aa2'.split(' '),
+    'a'
+  ]);
+}));
+
+// To test custom completer function.
+// Async mode.
+const testCustomCompleterAsyncMode = repl.start({
+  prompt: '',
+  input: putIn,
+  output: putIn,
+  completer: function completerAsyncMode(line, callback) {
+    const hits = customCompletions.filter((c) => {
+      return c.indexOf(line) === 0;
+    });
+    // Show all completions if none found.
+    callback(null, [hits.length ? hits : customCompletions, line]);
+  }
+});
+
+// On empty line should output all the custom completions
+// without complete anything.
+testCustomCompleterAsyncMode.complete('', common.mustCall((error, data) => {
+  assert.deepStrictEqual(data, [
+    customCompletions,
+    ''
+  ]);
+}));
+
+// On `a` should output `aaa aa1 aa2` and complete until `aa`.
+testCustomCompleterAsyncMode.complete('a', common.mustCall((error, data) => {
+  assert.deepStrictEqual(data, [
+    'aaa aa1 aa2'.split(' '),
+    'a'
+  ]);
+}));