feat: random numeric (#797)

Co-authored-by: ST-DDT <[email protected]>

1 files changed, 58 insertions, 0 deletions

diff --git a/src/random.ts b/src/random.ts
index 96128dd5..c349c92f 100644
--- a/src/random.ts
+++ b/src/random.ts
@@ -528,6 +528,64 @@ export class Random {
   }
 
   /**
+   * Generates a given length string of digits.
+   *
+   * @param length The number of digits to generate. Defaults to `1`.
+   * @param options The options to use. Defaults to `{}`.
+   * @param options.allowLeadingZeros If true, leading zeros will be allowed. Defaults to `false`.
+   * @param options.bannedDigits An array of digits which should be banned in the generated string. Defaults to `[]`.
+   *
+   * @example
+   * faker.random.numeric() // '2'
+   * faker.random.numeric(5) // '31507'
+   * faker.random.numeric(42) // '56434563150765416546479875435481513188548'
+   * faker.random.numeric(42, { allowLeadingZeros: true }) // '00564846278453876543517840713421451546115'
+   * faker.random.numeric(6, { bannedDigits: ['0'] }) // '943228'
+   */
+  numeric(
+    length: number = 1,
+    options: {
+      allowLeadingZeros?: boolean;
+      bannedDigits?: readonly string[];
+    } = {}
+  ): string {
+    if (length <= 0) {
+      return '';
+    }
+
+    const { allowLeadingZeros = false, bannedDigits = [] } = options;
+
+    const allowedDigits = '0123456789'
+      .split('')
+      .filter((digit) => !bannedDigits.includes(digit));
+
+    if (
+      allowedDigits.length === 0 ||
+      (allowedDigits.length === 1 &&
+        !allowLeadingZeros &&
+        allowedDigits[0] === '0')
+    ) {
+      throw new FakerError(
+        'Unable to generate numeric string, because all possible digits are banned.'
+      );
+    }
+
+    let result = '';
+
+    if (!allowLeadingZeros && !bannedDigits.includes('0')) {
+      result += this.arrayElement(
+        allowedDigits.filter((digit) => digit !== '0')
+      );
+    }
+
+    while (result.length < length) {
+      result += this.arrayElement(allowedDigits);
+    }
+
+    return result;
+  }
+
+  /**
    * Returns a hexadecimal number.
    *
    * @param count Length of the generated number. Defaults to `1`.