Add isbn-verifier exercise

config.json

@@ -55,6 +55,14 @@
         "prerequisites": [],
         "difficulty": 3
       },
+      {
+        "slug": "isbn-verifier",
+        "name": "Isbn Verifier",
+        "uuid": "952efb86-f0a3-432a-8751-614c431d9021",
+        "practices": [],
+        "prerequisites": [],
+        "difficulty": 4
+      },
       {
         "slug": "square-root",
         "name": "Square Root",

exercises/practice/isbn-verifier/.docs/instructions.append.md

@@ -0,0 +1,5 @@
+# Instruction append
+
+## Reserved Memory
+
+The buffer for the input string uses bytes 64-319 of linear memory.

exercises/practice/isbn-verifier/.docs/instructions.md

@@ -0,0 +1,42 @@
+# Instructions
+
+The [ISBN-10 verification process][isbn-verification] is used to validate book identification numbers.
+These normally contain dashes and look like: `3-598-21508-8`
+
+## ISBN
+
+The ISBN-10 format is 9 digits (0 to 9) plus one check character (either a digit or an X only).
+In the case the check character is an X, this represents the value '10'.
+These may be communicated with or without hyphens, and can be checked for their validity by the following formula:
+
+```text
+(d₁ * 10 + d₂ * 9 + d₃ * 8 + d₄ * 7 + d₅ * 6 + d₆ * 5 + d₇ * 4 + d₈ * 3 + d₉ * 2 + d₁₀ * 1) mod 11 == 0
+```
+
+If the result is 0, then it is a valid ISBN-10, otherwise it is invalid.
+
+## Example
+
+Let's take the ISBN-10 `3-598-21508-8`.
+We plug it in to the formula, and get:
+
+```text
+(3 * 10 + 5 * 9 + 9 * 8 + 8 * 7 + 2 * 6 + 1 * 5 + 5 * 4 + 0 * 3 + 8 * 2 + 8 * 1) mod 11 == 0
+```
+
+Since the result is 0, this proves that our ISBN is valid.
+
+## Task
+
+Given a string the program should check if the provided string is a valid ISBN-10.
+Putting this into place requires some thinking about preprocessing/parsing of the string prior to calculating the check digit for the ISBN.
+
+The program should be able to verify ISBN-10 both with and without separating dashes.
+
+## Caveats
+
+Converting from strings to numbers can be tricky in certain languages.
+Now, it's even trickier since the check digit of an ISBN-10 may be 'X' (representing '10').
+For instance `3-598-21507-X` is a valid ISBN-10.
+
+[isbn-verification]: https://en.wikipedia.org/wiki/International_Standard_Book_Number

exercises/practice/isbn-verifier/.eslintrc

@@ -0,0 +1,18 @@
+{
+  "root": true,
+  "extends": "@exercism/eslint-config-javascript",
+  "env": {
+    "jest": true
+  },
+  "overrides": [
+    {
+      "files": [
+        "*.spec.js"
+      ],
+      "excludedFiles": [
+        "custom.spec.js"
+      ],
+      "extends": "@exercism/eslint-config-javascript/maintainers"
+    }
+  ]
+}

exercises/practice/isbn-verifier/.meta/config.json

@@ -0,0 +1,28 @@
+{
+  "authors": [
+    "keiravillekode"
+  ],
+  "files": {
+    "solution": [
+      "isbn-verifier.wat"
+    ],
+    "test": [
+      "isbn-verifier.spec.js"
+    ],
+    "example": [
+      ".meta/proof.ci.wat"
+    ],
+    "invalidator": [
+      "package.json"
+    ]
+  },
+  "blurb": "Check if a given string is a valid ISBN-10 number.",
+  "source": "Converting a string into a number and some basic processing utilizing a relatable real world example.",
+  "source_url": "https://en.wikipedia.org/wiki/International_Standard_Book_Number#ISBN-10_check_digit_calculation",
+  "custom": {
+    "version.tests.compatibility": "jest-27",
+    "flag.tests.task-per-describe": false,
+    "flag.tests.may-run-long": false,
+    "flag.tests.includes-optional": false
+  }
+}

exercises/practice/isbn-verifier/.meta/proof.ci.wat

@@ -0,0 +1,115 @@
+(module
+  (memory (export "mem") 1)
+
+  (global $HYPHEN i32 (i32.const 45))
+
+  (global $ZERO i32 (i32.const 48))
+
+  (global $NINE i32 (i32.const 57))
+
+  (global $X i32 (i32.const 88))
+
+  ;;
+  ;; Checks if a string is a valid ISBN-10 number.
+  ;;
+  ;; @param {i32} offset - offset of string in linear memory
+  ;; @param {i32} length - length of string in linear memory
+  ;;
+  ;; @returns {i32} 1 if valid ISBN-10 number, 0 otherwise
+  ;;
+  (func (export "isValid") (param $offset i32) (param $length i32) (result i32)
+
+    (local $index i32)
+    (local $stop i32)
+    (local $remaining i32)
+    (local $value i32)
+    (local $total i32)
+    (local $weightedTotal i32)
+
+    (local.set $index (local.get $offset))
+    (local.set $stop
+      (i32.add
+        (local.get $offset)
+        (local.get $length)
+      )
+    )
+    (local.set $remaining (i32.const 10))
+    (local.set $total (i32.const 0))
+    (local.set $weightedTotal (i32.const 0))
+
+    (loop
+      (if (i32.eq (local.get $index) (local.get $stop))
+        (then
+          (return (i32.and (i32.eq (local.get $remaining) (i32.const 0))
+                           (i32.eq (i32.rem_u (local.get $weightedTotal) (i32.const 11)) (i32.const 0))))
+        )
+      )
+
+      (local.set $value (i32.load8_u (local.get $index)))
+
+      (local.set
+        $index
+        (i32.add
+          (local.get $index)
+          (i32.const 1)
+        )
+      )
+
+      (br_if 0 (i32.eq (local.get $value) (global.get $HYPHEN)))
+
+      (local.set
+        $remaining
+        (i32.sub
+          (local.get $remaining)
+          (i32.const 1)
+        )
+      )
+
+      (if (i32.or (i32.lt_u (local.get $value) (global.get $ZERO))
+                  (i32.gt_u (local.get $value) (global.get $NINE)))
+        (then
+          (if (i32.and (i32.eq (local.get $value) (global.get $X))
+                       (i32.eq (local.get $remaining) (i32.const 0)))
+            (then
+              (local.set
+                $value
+                (i32.const 10)
+              )
+            )
+            (else
+              (return (i32.const 0))
+            )
+          )
+        )
+        (else
+          (local.set
+            $value
+            (i32.sub
+              (local.get $value)
+              (global.get $ZERO)
+            )
+          )
+        )
+      )
+
+      (local.set
+        $total
+        (i32.add
+          (local.get $total)
+          (local.get $value)
+        )
+      )
+
+      (local.set
+        $weightedTotal
+        (i32.add
+          (local.get $weightedTotal)
+          (local.get $total)
+        )
+      )
+
+      (br 0)
+    )
+    (unreachable)
+  )
+)

exercises/practice/isbn-verifier/.meta/tests.toml

@@ -0,0 +1,67 @@
+# This is an auto-generated file.
+#
+# Regenerating this file via `configlet sync` will:
+# - Recreate every `description` key/value pair
+# - Recreate every `reimplements` key/value pair, where they exist in problem-specifications
+# - Remove any `include = true` key/value pair (an omitted `include` key implies inclusion)
+# - Preserve any other key/value pair
+#
+# As user-added comments (using the # character) will be removed when this file
+# is regenerated, comments can be added via a `comment` key.
+
+[0caa3eac-d2e3-4c29-8df8-b188bc8c9292]
+description = "valid isbn"
+
+[19f76b53-7c24-45f8-87b8-4604d0ccd248]
+description = "invalid isbn check digit"
+
+[4164bfee-fb0a-4a1c-9f70-64c6a1903dcd]
+description = "valid isbn with a check digit of 10"
+
+[3ed50db1-8982-4423-a993-93174a20825c]
+description = "check digit is a character other than X"
+
+[9416f4a5-fe01-4b61-a07b-eb75892ef562]
+description = "invalid check digit in isbn is not treated as zero"
+
+[c19ba0c4-014f-4dc3-a63f-ff9aefc9b5ec]
+description = "invalid character in isbn is not treated as zero"
+
+[28025280-2c39-4092-9719-f3234b89c627]
+description = "X is only valid as a check digit"
+
+[f6294e61-7e79-46b3-977b-f48789a4945b]
+description = "valid isbn without separating dashes"
+
+[185ab99b-3a1b-45f3-aeec-b80d80b07f0b]
+description = "isbn without separating dashes and X as check digit"
+
+[7725a837-ec8e-4528-a92a-d981dd8cf3e2]
+description = "isbn without check digit and dashes"
+
+[47e4dfba-9c20-46ed-9958-4d3190630bdf]
+description = "too long isbn and no dashes"
+
+[737f4e91-cbba-4175-95bf-ae630b41fb60]
+description = "too short isbn"
+
+[5458a128-a9b6-4ff8-8afb-674e74567cef]
+description = "isbn without check digit"
+
+[70b6ad83-d0a2-4ca7-a4d5-a9ab731800f7]
+description = "check digit of X should not be used for 0"
+
+[94610459-55ab-4c35-9b93-ff6ea1a8e562]
+description = "empty isbn"
+
+[7bff28d4-d770-48cc-80d6-b20b3a0fb46c]
+description = "input is 9 characters"
+
+[ed6e8d1b-382c-4081-8326-8b772c581fec]
+description = "invalid characters are not ignored after checking length"
+
+[daad3e58-ce00-4395-8a8e-e3eded1cdc86]
+description = "invalid characters are not ignored before checking length"
+
+[fb5e48d8-7c03-4bfb-a088-b101df16fdc3]
+description = "input is too long but contains a valid isbn"

exercises/practice/isbn-verifier/.npmrc

@@ -0,0 +1 @@
+audit=false

exercises/practice/isbn-verifier/LICENSE

@@ -0,0 +1,21 @@
+MIT License
+
+Copyright (c) 2021 Exercism
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in all
+copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
+SOFTWARE.

exercises/practice/isbn-verifier/babel.config.js

@@ -0,0 +1,4 @@
+export default {
+  presets: ["@exercism/babel-preset-javascript"],
+  plugins: [],
+};