58 lines
1.5 KiB
JavaScript
58 lines
1.5 KiB
JavaScript
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// Implementation of the Event Handler With State Pattern - Map Style
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/// Initialize user-provided state.
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/// State is stored inside an object map bound to 'state'.
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fn init() {
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// Add 'bool_state' as new state variable if one does not exist
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if !("bool_state" in state) {
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state.bool_state = false;
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}
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// Add 'obj_state' as new state variable (overwrites any existing)
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state.value = 0;
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// Can also add OOP-style functions!
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state.log = |x| print(`State = ${this.value}, data = ${x}`);
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}
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/// 'start' event handler
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fn start(data) {
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// Can detect system-provided default states!
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// Access state variables in 'state'
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if state.bool_state {
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throw "Already started!";
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}
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// New values can be added to the state
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state.start_mode = data;
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if state.value <= 0 {
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throw "Conditions not yet ready to start!";
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}
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state.bool_state = true;
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state.value = parse_int(data);
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// Constant 'MY_CONSTANT' in custom scope is also visible!
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print(`MY_CONSTANT = ${MY_CONSTANT}`);
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}
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/// 'end' event handler
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fn end(data) {
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if !state.bool_state || !("start_mode" in state) {
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throw "Not yet started!";
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}
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if state.value > 0 {
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throw "Conditions not yet ready to end!";
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}
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state.bool_state = false;
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state.value = parse_int(data);
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}
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/// 'update' event handler
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fn update(data) {
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let data = parse_int(data);
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state.value += data;
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// Call user-defined function OOP-style!
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state.log(data);
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}
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