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repl: docs-only deprecation of magic mode

The workaround used in repl to support `let` and `const` in non-strict
mode (known as "magic" mode) has been unnecessary since V8 v4.9 /
Node.js v6.0.0. This commit doc-deprecate magic mode (which is now
entirely equivalent to sloppy mode) in both `repl` module and in
`internal/repl`, which is responsible for starting the REPL in `node`
interactive mode.

PR-URL: #11599
Reviewed-By: Ben Noordhuis <>
Reviewed-By: James M Snell <>
Reviewed-By: Colin Ihrig <>
Reviewed-By: Prince John Wesley <>
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TimothyGu committed Feb 28, 2017
1 parent b77c890 commit 3f27f02da04b70120b397eeee904ff92784644ac
Showing with 25 additions and 11 deletions.
  1. +14 −0 doc/api/
  2. +8 −7 doc/api/
  3. +2 −3 lib/internal/repl.js
  4. +1 −1 lib/repl.js
@@ -542,6 +542,20 @@ Type: Runtime
The `tls.createSecurePair()` API was deprecated in documentation in Node.js
0.11.3. Users should use `tls.Socket` instead.
+<a id="DEP0065"></a>
+### DEP0065: repl.REPL_MODE_MAGIC and NODE_REPL_MODE=magic
+Type: Documentation-only
+The `repl` module's `REPL_MODE_MAGIC` constant, used for `replMode` option, has
+been deprecated. Its behavior has been functionally identical to that of
+`REPL_MODE_SLOPPY` since Node.js v6.0.0, when V8 5.0 was imported. Please use
+`REPL_MODE_SLOPPY` instead.
+The `NODE_REPL_MODE` environment variable is used to set the underlying
+`replMode` of an interactive `node` session. Its default value, `magic`, is
+similarly deprecated in favor of `sloppy`.
[alloc]: buffer.html#buffer_class_method_buffer_alloc_size_fill_encoding
[alloc_unsafe_size]: buffer.html#buffer_class_method_buffer_allocunsafe_size
[`Buffer.allocUnsafeSlow(size)`]: buffer.html#buffer_class_method_buffer_allocunsafeslow_size
@@ -408,14 +408,15 @@ changes:
command before writing to `output`. Defaults to [`util.inspect()`][].
* `completer` {Function} An optional function used for custom Tab auto
completion. See [`readline.InterfaceCompleter`][] for an example.
- * `replMode` - A flag that specifies whether the default evaluator executes
- all JavaScript commands in strict mode, default mode, or a hybrid mode
- ("magic" mode.) Acceptable values are:
+ * `replMode` {symbol} A flag that specifies whether the default evaluator
+ executes all JavaScript commands in strict mode or default (sloppy) mode.
+ Acceptable values are:
* `repl.REPL_MODE_SLOPPY` - evaluates expressions in sloppy mode.
* `repl.REPL_MODE_STRICT` - evaluates expressions in strict mode. This is
equivalent to prefacing every repl statement with `'use strict'`.
- * `repl.REPL_MODE_MAGIC` - attempt to evaluates expressions in default
- mode. If expressions fail to parse, re-try in strict mode.
+ * `repl.REPL_MODE_MAGIC` - This value is **deprecated**, since enhanced
+ spec compliance in V8 has rendered magic mode unnecessary. It is now
+ equivalent to `repl.REPL_MODE_SLOPPY` (documented above).
* `breakEvalOnSigint` - Stop evaluating the current piece of code when
`SIGINT` is received, i.e. `Ctrl+C` is pressed. This cannot be used together
with a custom `eval` function. Defaults to `false`.
@@ -461,8 +462,8 @@ environment variables:
- `NODE_REPL_HISTORY_SIZE` - Defaults to `1000`. Controls how many lines of
history will be persisted if history is available. Must be a positive number.
- `NODE_REPL_MODE` - May be any of `sloppy`, `strict`, or `magic`. Defaults
- to `magic`, which will automatically run "strict mode only" statements in
- strict mode.
+ to `sloppy`, which will allow non-strict mode code to be run. `magic` is
+ **deprecated** and treated as an alias of `sloppy`.
### Persistent History
@@ -39,12 +39,11 @@ function createRepl(env, opts, cb) {
opts.replMode = {
if (opts.replMode === undefined) {
- opts.replMode = REPL.REPL_MODE_MAGIC;
+ opts.replMode = REPL.REPL_MODE_SLOPPY;
const historySize = Number(env.NODE_REPL_HISTORY_SIZE);
@@ -633,7 +633,7 @@ exports.REPLServer = REPLServer;
exports.REPL_MODE_SLOPPY = Symbol('repl-sloppy');
exports.REPL_MODE_STRICT = Symbol('repl-strict');
-exports.REPL_MODE_MAGIC = Symbol('repl-magic');
// prompt is a string to print on each line for the prompt,
// source is a stream to use for I/O, defaulting to stdin/stdout.

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