feature: support for Parameter.content (#5571)

* add `getParameterSchema` OAS helper

* use `Parameter.content.[firstKey].schema` as schema value when present

* `newValue` -> `initialValue`

* make `paramWithMeta` a const

* add trailing comma to `swagger2SchemaKeys`

* refactor `helpers` to a folder

* deprecate `src/core/utils.js` in favor of `src/core/helpers/`

* support `Parameter.content.[mediaType].schema` in validateParam

* reject `null` as an OAS3 object value

* expose Fetch errors in the browser console

* generate ParameterRow default values based on `content` values

* add tests for `getParameterSchema`

* remove debugger statement

* remove debugger statement

* don't apply `generatedSampleValue`s to parameters with `examples`

* remove extra semi

* disable JSON check in parameter runtime validation

* stringify JsonSchema_object textarea values

* add Cypress tests

* swagger-client@3.9.4

src/helpers/get-parameter-schema.js

@@ -0,0 +1,67 @@
+/**
+ * @prettier
+ */
+
+import Im from "immutable"
+
+const swagger2SchemaKeys = Im.Set.of(
+  "type",
+  "format",
+  "items",
+  "default",
+  "maximum",
+  "exclusiveMaximum",
+  "minimum",
+  "exclusiveMinimum",
+  "maxLength",
+  "minLength",
+  "pattern",
+  "maxItems",
+  "minItems",
+  "uniqueItems",
+  "enum",
+  "multipleOf"
+)
+
+/**
+ * Get the effective schema value for a parameter, or an empty Immutable.Map if
+ * no suitable schema can be found.
+ *
+ * Supports OpenAPI 3.0 `Parameter.content` priority -- since a Parameter Object
+ * cannot have both `schema` and `content`, this function ignores `schema` when
+ * `content` is present.
+ *
+ * @param {Immutable.Map} parameter The parameter to identify a schema for
+ * @param {object} config
+ * @param {boolean} config.isOAS3 Whether the parameter is from an OpenAPI 2.0
+ * or OpenAPI 3.0 definition
+ * @return {Immutable.Map} The desired schema
+ */
+export default function getParameterSchema(parameter, { isOAS3 } = {}) {
+  // Return empty Map if `parameter` isn't a Map
+  if (!Im.Map.isMap(parameter)) return Im.Map()
+
+  if (!isOAS3) {
+    // Swagger 2.0
+    if (parameter.get("in") === "body") {
+      return parameter.get("schema", Im.Map())
+    } else {
+      return parameter.filter((v, k) => swagger2SchemaKeys.includes(k))
+    }
+  }
+
+  // If we've reached here, the parameter is OpenAPI 3.0
+
+  if (parameter.get("content")) {
+    const parameterContentMediaTypes = parameter
+      .get("content", Im.Map({}))
+      .keySeq()
+
+    return parameter.getIn(
+      ["content", parameterContentMediaTypes.first(), "schema"],
+      Im.Map()
+    )
+  }
+
+  return parameter.get("schema", Im.Map())
+}