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app_vue/node_modules/nth-check/lib/esm/compile.js

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+import boolbase from "boolbase";
+/**
+ * Returns a function that checks if an elements index matches the given rule
+ * highly optimized to return the fastest solution.
+ *
+ * @param parsed A tuple [a, b], as returned by `parse`.
+ * @returns A highly optimized function that returns whether an index matches the nth-check.
+ * @example
+ *
+ * ```js
+ * const check = nthCheck.compile([2, 3]);
+ *
+ * check(0); // `false`
+ * check(1); // `false`
+ * check(2); // `true`
+ * check(3); // `false`
+ * check(4); // `true`
+ * check(5); // `false`
+ * check(6); // `true`
+ * ```
+ */
+export function compile(parsed) {
+    const a = parsed[0];
+    // Subtract 1 from `b`, to convert from one- to zero-indexed.
+    const b = parsed[1] - 1;
+    /*
+     * When `b <= 0`, `a * n` won't be lead to any matches for `a < 0`.
+     * Besides, the specification states that no elements are
+     * matched when `a` and `b` are 0.
+     *
+     * `b < 0` here as we subtracted 1 from `b` above.
+     */
+    if (b < 0 && a <= 0)
+        return boolbase.falseFunc;
+    // When `a` is in the range -1..1, it matches any element (so only `b` is checked).
+    if (a === -1)
+        return (index) => index <= b;
+    if (a === 0)
+        return (index) => index === b;
+    // When `b <= 0` and `a === 1`, they match any element.
+    if (a === 1)
+        return b < 0 ? boolbase.trueFunc : (index) => index >= b;
+    /*
+     * Otherwise, modulo can be used to check if there is a match.
+     *
+     * Modulo doesn't care about the sign, so let's use `a`s absolute value.
+     */
+    const absA = Math.abs(a);
+    // Get `b mod a`, + a if this is negative.
+    const bMod = ((b % absA) + absA) % absA;
+    return a > 1
+        ? (index) => index >= b && index % absA === bMod
+        : (index) => index <= b && index % absA === bMod;
+}
+/**
+ * Returns a function that produces a monotonously increasing sequence of indices.
+ *
+ * If the sequence has an end, the returned function will return `null` after
+ * the last index in the sequence.
+ *
+ * @param parsed A tuple [a, b], as returned by `parse`.
+ * @returns A function that produces a sequence of indices.
+ * @example <caption>Always increasing (2n+3)</caption>
+ *
+ * ```js
+ * const gen = nthCheck.generate([2, 3])
+ *
+ * gen() // `1`
+ * gen() // `3`
+ * gen() // `5`
+ * gen() // `8`
+ * gen() // `11`
+ * ```
+ *
+ * @example <caption>With end value (-2n+10)</caption>
+ *
+ * ```js
+ *
+ * const gen = nthCheck.generate([-2, 5]);
+ *
+ * gen() // 0
+ * gen() // 2
+ * gen() // 4
+ * gen() // null
+ * ```
+ */
+export function generate(parsed) {
+    const a = parsed[0];
+    // Subtract 1 from `b`, to convert from one- to zero-indexed.
+    let b = parsed[1] - 1;
+    let n = 0;
+    // Make sure to always return an increasing sequence
+    if (a < 0) {
+        const aPos = -a;
+        // Get `b mod a`
+        const minValue = ((b % aPos) + aPos) % aPos;
+        return () => {
+            const val = minValue + aPos * n++;
+            return val > b ? null : val;
+        };
+    }
+    if (a === 0)
+        return b < 0
+            ? // There are no result — always return `null`
+                () => null
+            : // Return `b` exactly once
+                () => (n++ === 0 ? b : null);
+    if (b < 0) {
+        b += a * Math.ceil(-b / a);
+    }
+    return () => a * n++ + b;
+}
+//# sourceMappingURL=compile.js.map