Block-level /*flow-disable*/ and /*flow-enable*/

[agentcooper]

Will something like conditional comments make sense for Flow? There are some use cases (custom template inlines [1] or #718 [2]) when stripping some lines will allow Flow to understand the file.

Basic implementation I tested:

diff --git a/src/parsing/parsing_service_js.ml b/src/parsing/parsing_service_js.ml
index 8458cbc..a61b134 100644
--- a/src/parsing/parsing_service_js.ml
+++ b/src/parsing/parsing_service_js.ml
@@ -86,7 +86,7 @@ let do_parse ?(keep_errors=false) content file =
  * Add success/error info to passed accumulator. *)
 let reducer init_modes (ok, fails, errors) file =
   init_modes ();
-  let content = cat file in
+  let content = Str.global_replace (Str.regexp "/\\*flow-disable\\*/.+/\\*flow-enable\\*/") "" (cat file) in
   match (do_parse content file) with
   | OK ast ->
       ParserHeap.add file ast;

[1]

(function() {
  /*flow-disable*/{% include "lib.js" %}/*flow-enable*/
  lib.someFunction();
})();

[2]

// Flow will treat module as CommonJS

/*flow-disable*/define('banana', function(require, exports, module) {/*flow-enable*/
    module.exports = {
        render: function()/*: string*/ {
            return (
                '<p>banana</p>'
            );
        }
    };
/*flow-disable*/});/*flow-enable*/

[ab-5v]

+1

[gregegan]

+1

[echenley]

FYI, you can disable flow warnings using options.suppress_comment (https://flowtype.org/docs/advanced-configuration.html#options).

Example (taken from above link):

[options]
suppress_comment= \\(.\\|\n\\)*\\$FlowIgnore

// $FlowIgnore: suppressing this error
var x : string = 123;

[nmn]

Closing as resolved.

[shamas]

There is a default // $FlowFixMe defined to suppress the next line

https://flow.org/en/docs/config/options/#toc-suppress-comment-regex

[BrendanFDMoore]

This works, of course, but doesn't allow for block disabling, only line-by-line suppression. It can be a bit messy to add an ignore on each line in a block.

[dandonahoe]

This isn't a solution to the stated problem in the original post.

Blocks enable-disable should work just like eslint.

Example:

This is hideous

// $FlowFixMe
type Props = {|
  // $FlowFixMe
  onOrderInputChanged : Function,

  // $FlowFixMe
  personAssignmentId : string,

  // $FlowFixMe
  actionTypeId : PropTypeActionType,

  // $FlowFixMe
  orderSetId : string,
  orderValue : Immutable.Map,

  // $FlowFixMe
  activityId : string,
  order      : Immutable.Map
|};

This should be the correct solution

/* flow-disable */

type Props = {|
  onOrderInputChanged : Function,
  personAssignmentId  : string,
  actionTypeId        : PropTypeActionType,
  orderSetId          : string,
  orderValue          : Immutable.Map,
  activityId          : string,
  order               : Immutable.Map
|};

/* flow-enable */

[3stacks]

Doesn't seem like this issue is resolved. People still seem to want this feature.

[tanohzana]

Is there a PR related to this issue ? This feature is key in my opinion 🤔

[Aarbel]

Any news about this issue ?

Block disabling would a great tool to progressively implement Flow in an existing codebase