Setup spotlight project

.stoplight/custom-functions/oasOpParams.js

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+function isObject(value) {
+  return value !== null && typeof value === 'object';
+}
+
+function computeFingerprint(param) {
+  return `${String(param.in)}-${String(param.name)}`;
+}
+
+export const oasOpParams = (params, _opts, { path }) => {
+  /**
+   * This function verifies:
+   *
+   * 1. Operations must have unique `name` + `in` parameters.
+   * 2. Operation cannot have both `in:body` and `in:formData` parameters
+   * 3. Operation must have only one `in:body` parameter.
+   */
+
+  if (!Array.isArray(params)) return;
+
+  if (params.length < 2) return;
+
+  const results = [];
+
+  const count = {
+    body: [],
+    formData: [],
+  };
+  const list = [];
+  const duplicates = [];
+
+  let index = -1;
+
+  for (const param of params) {
+    index++;
+
+    if (!isObject(param)) continue;
+
+    // skip params that are refs
+    if ('$ref' in param) continue;
+
+    // Operations must have unique `name` + `in` parameters.
+    const fingerprint = computeFingerprint(param);
+    if (list.includes(fingerprint)) {
+      duplicates.push(index);
+    } else {
+      list.push(fingerprint);
+    }
+
+    if (typeof param.in === 'string' && param.in in count) {
+      count[param.in].push(index);
+    }
+  }
+
+  if (duplicates.length > 0) {
+    for (const i of duplicates) {
+      results.push({
+        message: 'A parameter in this operation already exposes the same combination of "name" and "in" values.',
+        path: [...path, i],
+      });
+    }
+  }
+
+  if (count.body.length > 0 && count.formData.length > 0) {
+    results.push({
+      message: 'Operation must not have both "in:body" and "in:formData" parameters.',
+    });
+  }
+
+  if (count.body.length > 1) {
+    for (let i = 1; i < count.body.length; i++) {
+      results.push({
+        message: 'Operation must not have more than a single instance of the "in:body" parameter.',
+        path: [...path, count.body[i]],
+      });
+    }
+  }
+
+  return results;
+};
+
+export default oasOpParams;