Class ScriptProperties

ScriptProperties.deleteAllProperties();

ScriptProperties.deleteProperty('special');

ScriptProperties.setProperties({
  "cow"     : "moo",
  "sheep"   : "baa",
  "chicken" : "cluck"
});

// Logs "A cow goes: moo"
Logger.log("A cow goes: %s", ScriptProperties.getProperty("cow"));

// This makes a copy. Any changes that happen here will not
// be written back to properties.
var animalSounds = ScriptProperties.getProperties();

// Logs:
// A chicken goes cluck!
// A cow goes moo!
// A sheep goes baa!
for(var kind in animalSounds) {
  Logger.log("A %s goes %s!", kind, animalSounds[kind]);
}

const specialValue = ScriptProperties.getProperty('special');

ScriptProperties.setProperties({special: 'sauce', 'meaning': 42});

// This deletes all other properties
ScriptProperties.setProperties({special: 'sauce', 'meaning': 42}, true);

ScriptProperties.setProperty('special', 'sauce');