basic csv support

+ csv imports
+ import options
+ type detection
+ bool, number, date, text, email and json types supported

utils/regex.ts

@@ -0,0 +1,143 @@
+import { RawRow } from "../types/csv.ts";
+
+/**
+ * Checks if the column type could be `Bool`.
+ * @param data - Sample data
+ * @param prop - Validated property
+ * @returns
+ */
+export function isBool(data: RawRow[], prop: string): boolean {
+  const zeroOrOne = /^(0|1)$/;
+  const trueOrFalse = /^(true|false)$/;
+
+  let values = 0;
+  let matched = 0;
+
+  try {
+    data.forEach((obj) => {
+      // could be nullable
+      if (obj[prop] !== "") {
+        values++;
+        if (
+          obj[prop].match(zeroOrOne) !== null ||
+          obj[prop].match(trueOrFalse) !== null
+        ) {
+          matched++;
+        }
+      }
+    });
+  } catch (e) {
+    console.error(e);
+  }
+
+  // an empty column will return false
+  return matched === values && matched > 0;
+}
+
+/**
+ * Checks if the column type could be `Number` (integer or floating point).
+ * @param data - Sample data
+ * @param prop - Validated property
+ * @returns
+ */
+export function isNumber(data: RawRow[], prop: string): boolean {
+  const integer = /^-?[0-9]+$/;
+  const float = /^-?[0-9]+\.[0-9]*$/;
+
+  let values = 0;
+  let matched = 0;
+
+  data.forEach((obj) => {
+    // could be nullable
+    if (obj[prop] !== "") {
+      values++;
+      if (
+        obj[prop].match(integer) !== null ||
+        obj[prop].match(float) !== null
+      ) {
+        matched++;
+      }
+    }
+  });
+
+  // an empty column will return false
+  return matched === values && matched > 0;
+}
+
+/**
+ * Checks if the column type could be `Email`.
+ * @param data - Sample data
+ * @param prop - Validated property
+ * @returns
+ */
+export function isEmail(data: RawRow[], prop: string): boolean {
+  const pattern = /^[\w-\.]+@([\w-]+\.)+[\w-]{2,4}$/;
+
+  let values = 0;
+  let matched = 0;
+
+  data.forEach((obj) => {
+    // could be nullable
+    if (obj[prop] !== "") {
+      values++;
+      if (obj[prop].match(pattern) !== null) {
+        matched++;
+      }
+    }
+  });
+
+  // an empty column will return false
+  return matched === values && matched > 0;
+}
+
+/**
+ * Parses the column values as JSON.
+ * @param data - Sample data
+ * @param prop - Validated property
+ * @returns
+ */
+export function isJson(data: RawRow[], prop: string): boolean {
+  let values = 0;
+  let parsed = 0;
+
+  data.forEach((obj) => {
+    // could be nullable
+    if (obj[prop] !== "") {
+      values++;
+      // looks for an exception
+      try {
+        JSON.parse(obj[prop]);
+        parsed++;
+      } // deno-lint-ignore no-empty
+      catch {}
+    }
+  });
+
+  // an empty column will return false
+  return parsed === values && parsed > 0;
+}
+
+/**
+ * Parses the column values using `Date.parse()`.
+ * @param data - Sample data
+ * @param prop - Validated property
+ * @returns
+ */
+export function isDate(data: RawRow[], prop: string): boolean {
+  let values = 0;
+  let parsed = 0;
+
+  data.forEach((obj) => {
+    // could be nullable
+    if (obj[prop] !== "") {
+      values++;
+      const timestamp = Date.parse(obj[prop]);
+      if (!isNaN(timestamp)) {
+        parsed++;
+      }
+    }
+  });
+
+  // an empty column will return false
+  return parsed === values && parsed > 0;
+}