v5

node_modules/once/once.js

@@ -0,0 +1,42 @@
+var wrappy = require('wrappy')
+module.exports = wrappy(once)
+module.exports.strict = wrappy(onceStrict)
+
+once.proto = once(function () {
+  Object.defineProperty(Function.prototype, 'once', {
+    value: function () {
+      return once(this)
+    },
+    configurable: true
+  })
+
+  Object.defineProperty(Function.prototype, 'onceStrict', {
+    value: function () {
+      return onceStrict(this)
+    },
+    configurable: true
+  })
+})
+
+function once (fn) {
+  var f = function () {
+    if (f.called) return f.value
+    f.called = true
+    return f.value = fn.apply(this, arguments)
+  }
+  f.called = false
+  return f
+}
+
+function onceStrict (fn) {
+  var f = function () {
+    if (f.called)
+      throw new Error(f.onceError)
+    f.called = true
+    return f.value = fn.apply(this, arguments)
+  }
+  var name = fn.name || 'Function wrapped with `once`'
+  f.onceError = name + " shouldn't be called more than once"
+  f.called = false
+  return f
+}