Add toIntegralNumber to numeric.js

[Pisces] / numeric.js

diff --git a/numeric.js b/numeric.js
index 78ea64c50aa080746ac4a206e41e71b2c5ebb017..64d9a80502f5fc8b363d59acb5aa18d9e5e988d7 100644 (file)
--- a/numeric.js
+++ b/numeric.js
@@ -377,6 +377,12 @@ export const {
   isSafeInteger: isSafeIntegralNumber,
 } = Number;
 
+/** Positive zero. */
+export const POSITIVE_ZERO = 0;
+
+/** Negative zero. */
+export const NEGATIVE_ZERO = -0;
+
 /**
  * Returns the magnitude (absolute value) of the provided value.
  *
@@ -560,10 +566,10 @@ export const sgn = ($) => {
     ? n === 0n ? 0n : n < 0n ? -1n : 1n
     : isNan(n) || n === 0
     ? n
-    : //deno-lint-ignore no-compare-neg-zero
-      n < -0
-      ? -1
-      : 1;
+    //deno-lint-ignore no-compare-neg-zero
+    : n < -0
+    ? -1
+    : 1;
 };
 
 /**
@@ -605,19 +611,75 @@ export const {
   return {
     toIntN: (n, $) => {
       const prim = toPrimitive($);
-      const big·int = toBigInt(prim);
-      const intN = asIntN(n, big·int);
-      return typeof prim === "bigint" ? intN : toNumber(intN);
+      if (typeof prim === "bigint") {
+        // The primitive value is a big·int.
+        return asIntN(n, prim);
+      } else {
+        // The primitive value is not a big·int.
+        const int = trunc(prim);
+        if (!isFiniteNumber(int) || int == 0) {
+          // The truncated value is zero or not finite.
+          return 0;
+        } else {
+          // The truncated value is finite.
+          return toNumber(asIntN(n, toBigInt(int)));
+        }
+      }
     },
     toUintN: (n, $) => {
       const prim = toPrimitive($);
-      const big·int = toBigInt(prim);
-      const uintN = asUintN(n, big·int);
-      return typeof prim === "bigint" ? uintN : toNumber(uintN);
+      if (typeof prim === "bigint") {
+        // The primitive value is a big·int.
+        return asUintN(n, prim);
+      } else {
+        // The primitive value is not a big·int.
+        const int = trunc(prim);
+        if (!isFiniteNumber(int) || int == 0) {
+          // The truncated value is zero or not finite.
+          return 0;
+        } else {
+          // The truncated value is finite.
+          return toNumber(asUintN(n, toBigInt(int)));
+        }
+      }
     },
   };
 })();
 
+/**
+ * Returns the result of converting the provided number to an integer
+ * or infinity.
+ *
+ * ※ This function will never return negative zero.
+ */
+export const toIntegerOrInfinity = ($) => {
+  const integer = trunc(toNumber($));
+  if (isNan(integer) || integer == 0) {
+    // The provided value truncs to nan or (positive or negative) zero.
+    return 0;
+  } else if (integer == POSITIVE_INFINITY) {
+    // The provided value truncs to positive infinity.
+    return POSITIVE_INFINITY;
+  } else if (integer == NEGATIVE_INFINITY) {
+    // The provided value truncs to negative infinity.
+    return NEGATIVE_INFINITY;
+  } else {
+    // The provided value truncs to an integer.
+    return integer;
+  }
+};
+
+/**
+ * Returns the result of converting the provided number to an integral
+ * number.
+ *
+ * ※ This function will never return negative zero.
+ */
+export const toIntegralNumber = ($) => {
+  const n = toIntegerOrInfinity($);
+  return !isFiniteNumber(n) || n == 0 ? 0 : n;
+};
+
 /**
  * Returns the result of converting the provided value to a number.
  *