From a85d2bf27ad273ef495bc97731f8a766048b8c70 Mon Sep 17 00:00:00 2001
From: Mahmoud Al-Qudsi <mqudsi@neosmart.net>
Date: Mon, 5 Mar 2018 08:28:19 -0600
Subject: [PATCH] Add intelligent package completion to yarn

Now parses package.json and uses results to provide a list of possible
completions to `yarn remove`. There may be other subcommands that could
benefit from this.

Could have parsed yarn output, but yarn is slow and packages.json format
is generally standard since it's machine-generated json.
---
 CHANGELOG.md                |  1 +
 share/completions/yarn.fish | 48 +++++++++++++++++++++++++++++++++++++
 2 files changed, 49 insertions(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index ba83484cb..56830a217 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -56,6 +56,7 @@ This section is for changes merged to the `major` branch that are not also merge
   - `git` (#4395, #4396, #4592)
   - `brew`
   - `diskutil`
+  - `yarn`
 
 --
 
diff --git a/share/completions/yarn.fish b/share/completions/yarn.fish
index 4266e9909..b27470fa6 100644
--- a/share/completions/yarn.fish
+++ b/share/completions/yarn.fish
@@ -2,6 +2,54 @@
 # see https://github.com/fish-shell/fish-shell/blob/master/share/functions/__fish_seen_subcommand_from.fish
 # and https://github.com/fish-shell/fish-shell/blob/master/share/functions/__fish_use_subcommand.fish
 
+function __yarn_find_package_json
+    set parents (__fish_parent_directories (pwd))
+
+    for p in $parents
+        if test -f "$p/package.json"
+            echo "$p/package.json"
+            return 0
+        end
+    end
+
+    return 1
+end
+
+function __yarn_list_packages
+    set -l package_json (__yarn_find_package_json)
+    if not test $status -eq 0
+        # no package.json in tree
+        return 1
+    end
+
+    set -l depsFound 0
+    for line in (cat $package_json)
+        # echo "evaluating $line"
+        if test $depsFound -eq 0
+            # echo "mode: noDeps"
+            if string match -qr '(devD|d)ependencies"' -- $line
+                # echo "switching to mode: deps"
+                set depsFound 1
+                continue
+            end
+            continue
+        end
+
+        if string match -qr '\}' -- $line
+            # echo "switching to mode: noDeps"
+            set depsFound 0
+            continue
+        end
+
+        # echo "mode: deps"
+
+        string replace -r '^\s*"([^"]+)".*' '$1' -- $line
+    end
+end
+
+
+complete -f -c yarn -n '__fish_seen_subcommand_from remove' -a (set -l packages (__yarn_list_packages); echo $packages)
+
 complete -f -c yarn -n '__fish_use_subcommand' -a help
 
 complete -f -c yarn -n '__fish_use_subcommand' -a access