Use nullish coalescing operator where applicable

Author: unematiii

src/core/Value.ts

@@ -12,8 +12,7 @@ export abstract class Value<D = unknown, S = D> extends Serializable {
   }
 
   protected extractValueFromJSONPayload(payload: unknown) {
-    const value = getValueFromObject(payload);
-    return value !== undefined ? value : payload;
+    return getValueFromObject(payload) ?? payload;
   }
 
   protected getValueForEncoding() {

src/values/DoubleValue.ts

@@ -17,6 +17,6 @@ export class DoubleValue extends FloatValue {
   }
 
   public toString() {
-    return (this._value !== undefined ? this._value : NaN).toPrecision(15);
+    return (this._value ?? NaN).toPrecision(15);
   }
 }

src/values/FloatValue.ts

@@ -35,7 +35,7 @@ export class FloatValue extends Value<number> {
   }
 
   public toString() {
-    return (this._value !== undefined ? this._value : NaN).toPrecision(7);
+    return (this._value ?? NaN).toPrecision(7);
   }
 
   public valueOf() {

src/values/IntegerValue.ts

@@ -35,6 +35,6 @@ export class IntegerValue extends Value<number> {
   }
 
   public valueOf() {
-    return this._value !== undefined ? this._value : null;
+    return this._value ?? null;
   }
 }