Refactor DeviceAttribute generics to eliminate "as T" assertions

src/device/attribute/boolDeviceAttribute.ts

@@ -1,19 +1,17 @@
-import type { DeviceAttributeModifier, NotJustUndefined, NotUndefined } from './deviceAttribute.js';
+import type { DeviceAttributeModifier } from './deviceAttribute.js';
 import DeviceAttribute from './deviceAttribute.js';
 
-type BoolDeviceAttributeValue = NotJustUndefined<boolean | undefined>;
+export type InitializedBoolDeviceAttribute = BoolDeviceAttribute<true>;
 
-export type InitializedBoolDeviceAttribute = BoolDeviceAttribute<boolean>;
-
-export default class BoolDeviceAttribute<T extends BoolDeviceAttributeValue = BoolDeviceAttributeValue> extends DeviceAttribute<T>
+export default class BoolDeviceAttribute<IsInitialized extends boolean = false> extends DeviceAttribute<boolean, IsInitialized>
 {
     public static createInitialized(
         name: string,
         label: string | undefined,
         modifier: DeviceAttributeModifier,
         initialValue: boolean,
     ): InitializedBoolDeviceAttribute {
-        return new BoolDeviceAttribute<boolean>(name, label, modifier, initialValue);
+        return new BoolDeviceAttribute<true>(name, label, modifier, initialValue);
     }
 
     public static create(
@@ -24,13 +22,11 @@ export default class BoolDeviceAttribute<T extends BoolDeviceAttributeValue = Bo
         return new BoolDeviceAttribute(name, label, modifier, undefined);
     }
 
-    public override fromString(value: string): T {
-        // TODO https://github.com/SlvCtrlPlus/slvctrlplus-server/issues/107
-        // eslint-disable-next-line @typescript-eslint/consistent-type-assertions, @typescript-eslint/no-unsafe-type-assertion
-        return (value === '1') as T;
+    public override fromString(value: string): boolean {
+        return value === '1';
     }
 
-    public override isValidValue(value: unknown): value is NotUndefined<T> {
+    public override isValidValue(value: unknown): value is boolean {
         return typeof value === 'boolean';
     }
 

src/device/attribute/deviceAttribute.ts

@@ -1,9 +1,9 @@
 import { Exclude, Expose } from 'class-transformer';
 import type { Float, Int } from '../../util/numbers.js';
 
-export type NotJustUndefined<V> = [V] extends [undefined] ? never : V;
-export type NotUndefined<V> = V extends undefined ? never : V;
-export type AttributeValue = NotJustUndefined<string | Int | Float | boolean | null | undefined>;
+export type AllowedAttributeType = string | Int | Float | boolean | null;
+
+export type AttributeValue<V extends AllowedAttributeType = AllowedAttributeType, IsInitialized extends boolean = false> = IsInitialized extends true ? V : V | undefined;
 
 export enum DeviceAttributeModifier
 {
@@ -12,13 +12,16 @@ export enum DeviceAttributeModifier
     writeOnly = 'wo',
 }
 
-export const isValidAttributeValue = <T extends AttributeValue>(
-    attribute: DeviceAttribute<T> | undefined,
+export const isValidAttributeValue = <V extends AllowedAttributeType, IsInitialized extends boolean = boolean>(
+    attribute: DeviceAttribute<V, IsInitialized> | undefined,
     value: unknown,
-): value is NotUndefined<T> => attribute?.isValidValue(value) ?? false;
+): value is V => attribute?.isValidValue(value) ?? false;
 
 @Exclude()
-export default abstract class DeviceAttribute<T extends AttributeValue = AttributeValue>
+export default abstract class DeviceAttribute<
+    V extends AllowedAttributeType = AllowedAttributeType,
+    IsInitialized extends boolean = false,
+>
 {
     @Expose({ name: 'name' })
     private readonly _name: string;
@@ -30,9 +33,9 @@ export default abstract class DeviceAttribute<T extends AttributeValue = Attribu
     private readonly _modifier: DeviceAttributeModifier;
 
     @Expose({ name: 'value' })
-    private _value: T;
+    private _value: AttributeValue<V, IsInitialized>;
 
-    public constructor(name: string, label: string | undefined, modifier: DeviceAttributeModifier, initialValue: T) {
+    public constructor(name: string, label: string | undefined, modifier: DeviceAttributeModifier, initialValue: AttributeValue<V, IsInitialized>) {
         this._name = name;
         this._label = label;
         this._modifier = modifier;
@@ -58,15 +61,15 @@ export default abstract class DeviceAttribute<T extends AttributeValue = Attribu
     /**
      * @returns the current value or undefined if it has never been set or read from the device
      */
-    public get value(): T {
+    public get value(): AttributeValue<V, IsInitialized> {
         return this._value;
     }
 
-    public set value(value: T) {
+    public set value(value: AttributeValue<V, IsInitialized>) {
         this._value = value;
     }
 
-    public hasValue(): this is { value: T } {
+    public hasValue(): this is { value: V } {
         return this._value !== undefined;
     }
 
@@ -76,7 +79,7 @@ export default abstract class DeviceAttribute<T extends AttributeValue = Attribu
         throw new Error(`Not implemented`);
     }
 
-    public abstract fromString(value: string): T;
+    public abstract fromString(value: string): V;
 
-    public abstract isValidValue(value: unknown): value is NotUndefined<T>;
+    public abstract isValidValue(value: unknown): value is V;
 }

src/device/attribute/floatDeviceAttribute.ts

@@ -1,19 +1,17 @@
-import type { DeviceAttributeModifier, NotJustUndefined } from './deviceAttribute.js';
+import type { AttributeValue, DeviceAttributeModifier } from './deviceAttribute.js';
 import { Float } from '../../util/numbers.js';
 import NumberDeviceAttribute from './numberDeviceAttribute.js';
 
-type FloatDeviceAttributeValue = NotJustUndefined<Float | undefined>;
+export type InitializedFloatGenericDeviceAttribute = FloatDeviceAttribute<true>;
 
-export type InitializedFloatGenericDeviceAttribute = FloatDeviceAttribute<Float>;
-
-export default class FloatDeviceAttribute<T extends FloatDeviceAttributeValue = FloatDeviceAttributeValue> extends NumberDeviceAttribute<T>
+export default class FloatDeviceAttribute<IsInitialized extends boolean = false> extends NumberDeviceAttribute<Float, IsInitialized>
 {
     public constructor(
         name: string,
         label: string | undefined,
         modifier: DeviceAttributeModifier,
         uom: string | undefined,
-        initialValue: T,
+        initialValue: AttributeValue<Float, IsInitialized>,
     ) {
         super(name, label, modifier, uom, initialValue);
     }
@@ -25,7 +23,7 @@ export default class FloatDeviceAttribute<T extends FloatDeviceAttributeValue =
         uom: string | undefined,
         initialValue: Float,
     ): InitializedFloatGenericDeviceAttribute {
-        return new FloatDeviceAttribute<Float>(name, label, modifier, uom, initialValue);
+        return new FloatDeviceAttribute<true>(name, label, modifier, uom, initialValue);
     }
 
     public static create(
@@ -37,16 +35,18 @@ export default class FloatDeviceAttribute<T extends FloatDeviceAttributeValue =
         return new FloatDeviceAttribute(name, label, modifier, uom, undefined);
     }
 
-    public fromString(value: string): T {
+    public fromString(value: string): Float {
         const num = parseFloat(value);
 
         if (isNaN(num)) {
             throw new Error(`Could not convert '${value}' to a valid value for ${this.constructor.name}`);
         }
 
-        // TODO https://github.com/SlvCtrlPlus/slvctrlplus-server/issues/107
-        // eslint-disable-next-line @typescript-eslint/consistent-type-assertions, @typescript-eslint/no-unsafe-type-assertion
-        return Float.from(num) as T;
+        return Float.from(num);
+    }
+
+    public override isValidValue(value: unknown): value is Float {
+        return typeof value === 'number' && Number.isFinite(value);
     }
 
     public override getType(): string {

src/device/attribute/intDeviceAttribute.ts

@@ -1,11 +1,10 @@
-import type { DeviceAttributeModifier, NotJustUndefined } from './deviceAttribute.js';
+import type { DeviceAttributeModifier } from './deviceAttribute.js';
 import { Int } from '../../util/numbers.js';
 import NumberDeviceAttribute from './numberDeviceAttribute.js';
 
-export type IntAttributeValue = NotJustUndefined<Int | undefined>;
-export type InitializedIntGenericDeviceAttribute = IntDeviceAttribute<Int>;
+export type InitializedIntGenericDeviceAttribute = IntDeviceAttribute<true>;
 
-export default class IntDeviceAttribute<T extends IntAttributeValue = IntAttributeValue> extends NumberDeviceAttribute<T>
+export default class IntDeviceAttribute<IsInitialized extends boolean = false> extends NumberDeviceAttribute<Int, IsInitialized>
 {
     public static createInitialized(
         name: string,
@@ -14,7 +13,7 @@ export default class IntDeviceAttribute<T extends IntAttributeValue = IntAttribu
         uom: string | undefined,
         initialValue: Int,
     ): InitializedIntGenericDeviceAttribute {
-        return new IntDeviceAttribute<Int>(name, label, modifier, uom, initialValue);
+        return new IntDeviceAttribute<true>(name, label, modifier, uom, initialValue);
     }
 
     public static create(
@@ -26,16 +25,18 @@ export default class IntDeviceAttribute<T extends IntAttributeValue = IntAttribu
         return new IntDeviceAttribute(name, label, modifier, uom, undefined);
     }
 
-    public fromString(value: string): T {
+    public fromString(value: string): Int {
         const num = parseInt(value, 10);
 
         if (isNaN(num)) {
             throw new Error(`Could not convert '${value}' to a valid value for ${this.constructor.name}`);
         }
 
-        // TODO https://github.com/SlvCtrlPlus/slvctrlplus-server/issues/107
-        // eslint-disable-next-line @typescript-eslint/consistent-type-assertions, @typescript-eslint/no-unsafe-type-assertion
-        return Int.from(num) as T;
+        return Int.from(num);
+    }
+
+    public override isValidValue(value: unknown): value is Int {
+        return typeof value === 'number' && Number.isInteger(value);
     }
 
     public override getType(): string {

src/device/attribute/intRangeDeviceAttribute.ts

@@ -1,12 +1,11 @@
 import { Expose } from 'class-transformer';
-import type { IntAttributeValue } from './intDeviceAttribute.js';
 import { Int } from '../../util/numbers.js';
-import type { DeviceAttributeModifier } from './deviceAttribute.js';
+import type { AttributeValue, DeviceAttributeModifier } from './deviceAttribute.js';
 import NumberDeviceAttribute from './numberDeviceAttribute.js';
 
-export type InitializedIntRangeDeviceAttribute = IntRangeDeviceAttribute<Int>;
+export type InitializedIntRangeDeviceAttribute = IntRangeDeviceAttribute<true>;
 
-export default class IntRangeDeviceAttribute<T extends IntAttributeValue = IntAttributeValue> extends NumberDeviceAttribute<T>
+export default class IntRangeDeviceAttribute<IsInitialized extends boolean = false> extends NumberDeviceAttribute<Int, IsInitialized>
 {
     @Expose({ name: 'min' })
     private _min: Int;
@@ -17,7 +16,16 @@ export default class IntRangeDeviceAttribute<T extends IntAttributeValue = IntAt
     @Expose({ name: 'incrementStep' })
     private readonly _incrementStep: Int = Int.from(1);
 
-    public constructor(name: string, label: string | undefined, modifier: DeviceAttributeModifier, uom: string | undefined, min: Int, max: Int, incrementStep: Int, initialValue: T) {
+    public constructor(
+        name: string,
+        label: string | undefined,
+        modifier: DeviceAttributeModifier,
+        uom: string | undefined,
+        min: Int,
+        max: Int,
+        incrementStep: Int,
+        initialValue: AttributeValue<Int, IsInitialized>,
+    ) {
         super(name, label, modifier, uom, initialValue);
         this._min = min;
         this._max = max;
@@ -34,7 +42,7 @@ export default class IntRangeDeviceAttribute<T extends IntAttributeValue = IntAt
         incrementStep: Int,
         initialValue: Int,
     ): InitializedIntRangeDeviceAttribute {
-        return new IntRangeDeviceAttribute<Int>(name, label, modifier, uom, min, max, incrementStep, initialValue);
+        return new IntRangeDeviceAttribute<true>(name, label, modifier, uom, min, max, incrementStep, initialValue);
     }
 
     public static create(
@@ -69,16 +77,18 @@ export default class IntRangeDeviceAttribute<T extends IntAttributeValue = IntAt
         return this._incrementStep;
     }
 
-    public fromString(value: string): T {
+    public fromString(value: string): Int {
         const res = parseInt(value, 10);
 
         if (isNaN(res)) {
             throw new Error(`Could not convert '${value}' to a valid value for ${this.constructor.name}`);
         }
 
-        // TODO https://github.com/SlvCtrlPlus/slvctrlplus-server/issues/107
-        // eslint-disable-next-line @typescript-eslint/consistent-type-assertions, @typescript-eslint/no-unsafe-type-assertion
-        return res as T;
+        return Int.from(res);
+    }
+
+    public override isValidValue(value: unknown): value is Int {
+        return typeof value === 'number' && Number.isInteger(value);
     }
 
     public override getType(): string {

src/device/attribute/listDeviceAttribute.ts

@@ -1,5 +1,5 @@
 import { Expose } from 'class-transformer';
-import type { DeviceAttributeModifier, NotUndefined } from './deviceAttribute.js';
+import type { AttributeValue, DeviceAttributeModifier } from './deviceAttribute.js';
 import DeviceAttribute from './deviceAttribute.js';
 import type { Int } from '../../util/numbers.js';
 
@@ -9,15 +9,15 @@ export type ListDeviceAttributeItem = string | Int;
 export type InitializedListDeviceAttribute<
     IKey extends ListDeviceAttributeItem,
     IValue extends ListDeviceAttributeItem,
-> = ListDeviceAttribute<IKey, IValue, IKey>;
+> = ListDeviceAttribute<IKey, IValue, true>;
 
 export type ListDeviceAttributeOptions<IKey, IValue> = ListDeviceAttributeOption<IKey, IValue>[];
 
 export default class ListDeviceAttribute<
     IKey extends ListDeviceAttributeItem,
     IValue extends ListDeviceAttributeItem,
-    V extends IKey | undefined = IKey | undefined,
-> extends DeviceAttribute<V>
+    IsInitialized extends boolean = false,
+> extends DeviceAttribute<IKey, IsInitialized>
 {
     @Expose({ name: 'values' })
     private _values: ListDeviceAttributeOptions<IKey, IValue>;
@@ -27,7 +27,7 @@ export default class ListDeviceAttribute<
         label: string | undefined,
         modifier: DeviceAttributeModifier,
         values: ListDeviceAttributeOptions<IKey, IValue>,
-        initialValue: V,
+        initialValue: AttributeValue<IKey, IsInitialized>,
     ) {
         super(name, label, modifier, initialValue);
 
@@ -41,7 +41,7 @@ export default class ListDeviceAttribute<
         values: ListDeviceAttributeOptions<IKey, IValue>,
         initialValue: IKey,
     ): InitializedListDeviceAttribute<IKey, IValue> {
-        return new ListDeviceAttribute<IKey, IValue, IKey>(
+        return new ListDeviceAttribute<IKey, IValue, true>(
             name, label, modifier, values, initialValue,
         );
     }
@@ -57,18 +57,18 @@ export default class ListDeviceAttribute<
         );
     }
 
-    public fromString(value: string): V {
+    public fromString(value: string): IKey {
         if (this._values.length === 0 || typeof this._values[0]?.key === 'string') {
-            // TODO https://github.com/SlvCtrlPlus/slvctrlplus-server/issues/107
+            // The value kind (IKey) is chosen by the caller per instance, so TypeScript can't
+            // prove `value`/the parsed number is an IKey here - see issue #107 for details.
             // eslint-disable-next-line @typescript-eslint/consistent-type-assertions, @typescript-eslint/no-unsafe-type-assertion
-            return value as V;
+            return value as IKey;
         }
 
         const parsedInt = parseInt(value, 10);
 
-        // TODO https://github.com/SlvCtrlPlus/slvctrlplus-server/issues/107
         // eslint-disable-next-line @typescript-eslint/consistent-type-assertions, @typescript-eslint/no-unsafe-type-assertion
-        return (isNaN(parsedInt) ? value : parsedInt) as V;
+        return (isNaN(parsedInt) ? value : parsedInt) as IKey;
     }
 
     public get values(): ListDeviceAttributeOptions<IKey, IValue> {
@@ -79,7 +79,7 @@ export default class ListDeviceAttribute<
         this._values = value;
     }
 
-    public isValidValue(value: unknown): value is NotUndefined<V> {
+    public isValidValue(value: unknown): value is IKey {
         if (typeof value === 'string' || typeof value === 'number') {
             return -1 !== this._values.findIndex(entry => entry.key === value);
         }

src/device/attribute/numberDeviceAttribute.ts

@@ -1,11 +1,14 @@
-import type { DeviceAttributeModifier, NotJustUndefined, NotUndefined } from './deviceAttribute.js';
+import type { AttributeValue, DeviceAttributeModifier } from './deviceAttribute.js';
 import DeviceAttribute from './deviceAttribute.js';
 import { Expose } from 'class-transformer';
 import type { Float, Int } from '../../util/numbers.js';
 
-export type NumberAttributeValue = NotJustUndefined<Int | Float | undefined>;
+export type NumberAttributeValue = Int | Float;
 
-export default abstract class NumberDeviceAttribute<T extends NumberAttributeValue = NumberAttributeValue> extends DeviceAttribute<T>
+export default abstract class NumberDeviceAttribute<
+    V extends NumberAttributeValue = NumberAttributeValue,
+    IsInitialized extends boolean = false,
+> extends DeviceAttribute<V, IsInitialized>
 {
     @Expose({ name: 'uom' })
     private readonly _uom: string | undefined;
@@ -15,7 +18,7 @@ export default abstract class NumberDeviceAttribute<T extends NumberAttributeVal
         label: string | undefined,
         modifier: DeviceAttributeModifier,
         uom: string | undefined,
-        initialValue: T,
+        initialValue: AttributeValue<V, IsInitialized>,
     ) {
         super(name, label, modifier, initialValue);
         this._uom = uom;
@@ -24,8 +27,4 @@ export default abstract class NumberDeviceAttribute<T extends NumberAttributeVal
     public get uom(): string | undefined {
         return this._uom;
     }
-
-    public override isValidValue(value: unknown): value is NotUndefined<T> {
-        return typeof value === 'number';
-    }
 }