Add comments for modifiers

src/game/modifiers.tsx

@@ -1,17 +1,45 @@
+import "components/common/modifiers.css";
 import { CoercableComponent, jsx } from "features/feature";
 import Decimal, { DecimalSource, format } from "util/bignum";
+import { WithRequired } from "util/common";
 import { Computable, convertComputable, ProcessedComputable } from "util/computed";
 import { renderJSX } from "util/vue";
 import { computed, unref } from "vue";
-import "components/common/modifiers.css";
 
+/**
+ * An object that can be used to apply or unapply some modification to a number.
+ * Being reversible requires the operation being invertible, but some features may rely on that.
+ * Descriptions can be optionally included for displaying them to the player.
+ * The built-in modifier creators are designed to display the modifiers using
+ * {@link createModifierSection}
+ */
 export interface Modifier {
+    /**
+     * Applies some operation on the input and returns the result
+     */
     apply: (gain: DecimalSource) => DecimalSource;
-    revert: (gain: DecimalSource) => DecimalSource;
-    enabled: ProcessedComputable<boolean>;
+    /**
+     * Reverses the operation applied by the apply property. Required by some features
+     */
+    revert?: (gain: DecimalSource) => DecimalSource;
+    /**
+     * Whether or not this modifier should be considered enabled.
+     * Typically for use with modifiers passed into {@link createSequentialModifier}
+     */
+    enabled?: ProcessedComputable<boolean>;
+    /**
+     * A description of this modifier.
+     * @see {@link createModifierSection}
+     */
     description?: ProcessedComputable<CoercableComponent>;
 }
 
+/**
+ * Create a modifier that adds some value to the input value
+ * @param addend The amount to add to the input value
+ * @param description Description of what this modifier is doing
+ * @param enabled A computable that will be processed and passed directly into the returned modifier
+ */
 export function createAdditiveModifier(
     addend: Computable<DecimalSource>,
     description?: Computable<CoercableComponent>,
@@ -19,12 +47,15 @@ export function createAdditiveModifier(
 ): Modifier {
     const processedAddend = convertComputable(addend);
     const processedDescription = convertComputable(description);
-    const processedEnabled = convertComputable(enabled == null ? true : enabled);
+    const processedEnabled = enabled == null ? undefined : convertComputable(enabled);
     return {
         apply: gain => Decimal.add(gain, unref(processedAddend)),
         revert: gain => Decimal.sub(gain, unref(processedAddend)),
         enabled: processedEnabled,
-        description: jsx(() => (
+        description:
+            description == null
+                ? undefined
+                : jsx(() => (
                       <div class="modifier-container">
                           <span class="modifier-amount">+{format(unref(processedAddend))}</span>
                           {unref(processedDescription) ? (
@@ -38,6 +69,12 @@ export function createAdditiveModifier(
     };
 }
 
+/**
+ * Create a modifier that multiplies the input value by some value
+ * @param multiplier The value to multiply the input value by
+ * @param description Description of what this modifier is doing
+ * @param enabled A computable that will be processed and passed directly into the returned modifier
+ */
 export function createMultiplicativeModifier(
     multiplier: Computable<DecimalSource>,
     description?: Computable<CoercableComponent>,
@@ -45,12 +82,15 @@ export function createMultiplicativeModifier(
 ): Modifier {
     const processedMultiplier = convertComputable(multiplier);
     const processedDescription = convertComputable(description);
-    const processedEnabled = convertComputable(enabled == null ? true : enabled);
+    const processedEnabled = enabled == null ? undefined : convertComputable(enabled);
     return {
         apply: gain => Decimal.times(gain, unref(processedMultiplier)),
         revert: gain => Decimal.div(gain, unref(processedMultiplier)),
         enabled: processedEnabled,
-        description: jsx(() => (
+        description:
+            description == null
+                ? undefined
+                : jsx(() => (
                       <div class="modifier-container">
                           <span class="modifier-amount">x{format(unref(processedMultiplier))}</span>
                           {unref(processedDescription) ? (
@@ -64,6 +104,12 @@ export function createMultiplicativeModifier(
     };
 }
 
+/**
+ * Create a modifier that raises the input value to the power of some value
+ * @param exponent The value to raise the input value to the power of
+ * @param description Description of what this modifier is doing
+ * @param enabled A computable that will be processed and passed directly into the returned modifier
+ */
 export function createExponentialModifier(
     exponent: Computable<DecimalSource>,
     description?: Computable<CoercableComponent>,
@@ -71,12 +117,15 @@ export function createExponentialModifier(
 ): Modifier {
     const processedExponent = convertComputable(exponent);
     const processedDescription = convertComputable(description);
-    const processedEnabled = convertComputable(enabled == null ? true : enabled);
+    const processedEnabled = enabled == null ? undefined : convertComputable(enabled);
     return {
         apply: gain => Decimal.pow(gain, unref(processedExponent)),
         revert: gain => Decimal.root(gain, unref(processedExponent)),
         enabled: processedEnabled,
-        description: jsx(() => (
+        description:
+            description == null
+                ? undefined
+                : jsx(() => (
                       <div class="modifier-container">
                           <span class="modifier-amount">^{format(unref(processedExponent))}</span>
                           {unref(processedDescription) ? (
@@ -90,22 +139,34 @@ export function createExponentialModifier(
     };
 }
 
-export function createSequentialModifier(...modifiers: Modifier[]): Required<Modifier> {
+/**
+ * Takes an array of modifiers and applies and reverses them in order.
+ * Modifiers that are not enabled will not be applied nor reversed.
+ * Also joins their descriptions together.
+ * @param modifiers The modifiers to perform sequentially
+ * @see {@link createModifierSection}
+ */
+export function createSequentialModifier(
+    ...modifiers: Modifier[]
+): WithRequired<Modifier, "description"> {
     return {
         apply: gain =>
             modifiers
-                .filter(m => unref(m.enabled))
+                .filter(m => unref(m.enabled) !== false)
                 .reduce((gain, modifier) => modifier.apply(gain), gain),
-        revert: gain =>
+        revert: modifiers.every(m => m.revert != null)
+            ? gain =>
                   modifiers
-                .filter(m => unref(m.enabled))
-                .reduceRight((gain, modifier) => modifier.revert(gain), gain),
-        enabled: computed(() => modifiers.filter(m => unref(m.enabled)).length > 0),
+                      .filter(m => unref(m.enabled) !== false)
+                      // eslint-disable-next-line @typescript-eslint/no-non-null-assertion
+                      .reduceRight((gain, modifier) => modifier.revert!(gain), gain)
+            : undefined,
+        enabled: computed(() => modifiers.filter(m => unref(m.enabled) !== false).length > 0),
         description: jsx(() => (
             <>
                 {(
                     modifiers
-                        .filter(m => unref(m.enabled))
+                        .filter(m => unref(m.enabled) !== false)
                         .map(m => unref(m.description))
                         .filter(d => d) as CoercableComponent[]
                 ).map(renderJSX)}
@@ -114,6 +175,16 @@ export function createSequentialModifier(...modifiers: Modifier[]): Required<Mod
     };
 }
 
+/**
+ * Create a JSX element that displays a modifier.
+ * Intended to be used with the output from {@link createSequentialModifier}
+ * @param title The header for the section
+ * @param subtitle Smaller text that appears in the header after the title
+ * @param modifier The modifier to render
+ * @param base The base value that'll be passed into the modifier
+ * @param unit The unit of the value being modified, if any
+ * @param baseText The label to use for the base value
+ */
 export function createModifierSection(
     title: string,
     subtitle: string,

src/util/common.ts

@@ -1,3 +1,5 @@
+export type WithRequired<T, K extends keyof T> = T & { [P in K]-?: T[P] };
+
 // Reference:
 // https://stackoverflow.com/questions/7225407/convert-camelcasetext-to-sentence-case-text
 export function camelToTitle(camel: string): string {