resolve #587

3 files changed, 92 insertions, 2 deletions

diff --git a/changelog.md b/changelog.md
index 6dd5f965..002cee3b 100644
--- a/changelog.md
+++ b/changelog.md
@@ -10,6 +10,24 @@
   + `different-requires`
 * `NEW` supports `---@CustomClass<string, number>`
 * `NEW` supports `$/cancelRequest`
+* `NEW` supports `EventEmitter`
+    ```lua
+    --- @class Emit
+    --- @field on fun(eventName: string, cb: function)
+    --- @field on fun(eventName: '"died"', cb: fun(i: integer))
+    --- @field on fun(eventName: '"won"', cb: fun(s: string))
+    local emit = {}
+
+    emit:on(--[[support autocomplete fr "died" and "won"]])
+
+    emit:on("died", function (i)
+        -- should be i: integer
+    end)
+
+    emit:on('won', function (s)
+        -- should be s: string
+    end)
+    ```
 * `CHG` hover: improve showing multi defines
 * `CHG` hover: improve showing multi comments at enums
 * `CHG` hint: `Lua.hint.paramName` now supports `Disable`, `Literal` and `All`
diff --git a/script/core/completion.lua b/script/core/completion.lua
index d27a32c5..a45c7a08 100644
--- a/script/core/completion.lua
+++ b/script/core/completion.lua
@@ -19,6 +19,7 @@ local lang         = require 'language'
 local lookBackward = require 'core.look-backward'
 local guide        = require 'parser.guide'
 local infer        = require 'core.infer'
+local noder        = require 'core.noder'
 
 local DiagnosticModes = {
     'disable-next-line',
@@ -1315,7 +1316,7 @@ local function pushCallEnumsAndFuncs(defs)
     return results
 end
 
-local function getCallEnumsAndFuncs(source, index, oop)
+local function getCallEnumsAndFuncs(source, index, oop, call)
     if source.type == 'function' and source.bindDocs then
         if not source.args then
             return
@@ -1361,6 +1362,50 @@ local function getCallEnumsAndFuncs(source, index, oop)
             return pushCallEnumsAndFuncs(vm.getDefs(arg.extends))
         end
     end
+    if source.type == 'doc.field.name' then
+        local currentIndex = index
+        if oop then
+            currentIndex = index - 1
+        end
+        local class = source.parent.class
+        if not class then
+            return
+        end
+        local results = {}
+        if currentIndex == 1 then
+            for _, doc in ipairs(class.fields) do
+                if  doc.field ~= source
+                and doc.field[1] == source[1] then
+                    local eventName = noder.getFieldEventName(doc)
+                    if eventName then
+                        results[#results+1] = {
+                            label       = ('%q'):format(eventName),
+                            description = doc.comment,
+                            kind        = define.CompletionItemKind.EnumMember,
+                        }
+                    end
+                end
+            end
+        elseif currentIndex == 2 then
+            local myEventName = call.args[index - 1][1]
+            for _, doc in ipairs(class.fields) do
+                if  doc.field ~= source
+                and doc.field[1] == source[1] then
+                    local eventName = noder.getFieldEventName(doc)
+                    if eventName and eventName == myEventName then
+                        local docFunc = doc.extends.types[1].args[2].extends.types[1]
+                        results[#results+1] = {
+                            label       = infer.viewDocFunction(docFunc),
+                            description = doc.comment,
+                            kind        = define.CompletionItemKind.Function,
+                            insertText  = buildInsertDocFunction(docFunc),
+                        }
+                    end
+                end
+            end
+        end
+        return results
+    end
 end
 
 local function findCall(state, text, position)
@@ -1494,7 +1539,7 @@ local function tryCallArg(state, text, position, results)
     local defs = vm.getDefs(call.node)
     for _, def in ipairs(defs) do
         def = searcher.getObjectValue(def) or def
-        local enums = getCallEnumsAndFuncs(def, argIndex, oop)
+        local enums = getCallEnumsAndFuncs(def, argIndex, oop, call)
         if enums then
             mergeEnums(myResults, enums, arg)
         end
diff --git a/test/completion/common.lua b/test/completion/common.lua
index c5740e15..62569d01 100644
--- a/test/completion/common.lua
+++ b/test/completion/common.lua
@@ -2632,3 +2632,30 @@ class2:<??>
 {
     [1] = EXISTS,
 }
+
+TEST [[
+--- @class Emit
+--- @field on fun(eventName: string, cb: function)
+--- @field on fun(eventName: '"died"', cb: fun(i: integer))
+--- @field on fun(eventName: '"won"', cb: fun(s: string))
+local emit = {}
+
+emit:on('<??>')
+]]
+(EXISTS)
+
+TEST [[
+--- @class Emit
+--- @field on fun(eventName: string, cb: function)
+--- @field on fun(eventName: '"died"', cb: fun(i: integer))
+--- @field on fun(eventName: '"won"', cb: fun(s: string))
+local emit = {}
+
+emit:on('won', <??>)
+]]
+{
+    [1] = {
+        label    = 'fun(s: string)',
+        kind     = define.CompletionItemKind.Function,
+    }
+}