Init commit with many years of arduino sketches and projects. I dont know if the esp8266 includes much, but there are also libraries. I hope they dont have crazy automatic versioning through the Arduino IDE.

Projects/_5_buttonTest/_5_buttonTest.ino

@@ -0,0 +1,21 @@
+const int buttonPin0 = 0;
+
+const int led = 13;
+
+void setup() {
+  pinMode(buttonPin0, INPUT);
+  pinMode(led, OUTPUT);
+  
+  Serial.begin(9600);
+}
+
+void loop() {
+if (analogRead(buttonPin0) == 0) {
+  digitalWrite(led, HIGH);
+}
+else {
+  digitalWrite(led, LOW);
+}
+  
+  delay(1000);
+}