Implement toCsv

package.json

@@ -24,7 +24,7 @@
     "@angular/platform-browser-dynamic": "^6.1.4",
     "@angular/router": "^6.1.4",
     "core-js": "^2.5.4",
-    "micro-dash": "^4.1.0",
+    "micro-dash": "^4.2.0",
     "rxjs": "^6.0.0",
     "zone.js": "~0.8.26"
   },

projects/s-js-utils/src/lib/to-csv.spec.ts

@@ -0,0 +1,72 @@
+import { toCsv } from "./to-csv";
+
+describe("toCsv()", () => {
+  it("works", () => {
+    expect(toCsv([["a", "b", "c"], ["d", "e", "f"], ["g", "h", "i"]])).toBe(
+      "a,b,c\nd,e,f\ng,h,i",
+    );
+  });
+
+  it("handles empty cells properly", () => {
+    expect(
+      toCsv([
+        ["middle", "", "empty"],
+        ["", "start", "empty"],
+        ["end", "empty", ""],
+      ]),
+    ).toBe("middle,,empty\n,start,empty\nend,empty,");
+  });
+
+  it("handles empty rows properly", () => {
+    expect(toCsv([["row"], [], ["another row"], []])).toBe(
+      "row\n\nanother row\n",
+    );
+  });
+
+  it("properly escapes double quotes", () => {
+    expect(toCsv([["escape", "csv", `"quotes"`]])).toBe(
+      `escape,csv,"""quotes"""`,
+    );
+  });
+
+  it("properly escapes commas", () => {
+    expect(
+      toCsv([["eats shoots and leaves", "eats, shoots, and leaves"]]),
+    ).toBe(`eats shoots and leaves,"eats, shoots, and leaves"`);
+  });
+
+  it("properly escapes new lines", () => {
+    expect(toCsv([["one", "1"], ["two", "1\n2"], ["three", "1\n2\n3"]])).toBe(
+      `one,1\ntwo,"1\n2"\nthree,"1\n2\n3"`,
+    );
+    expect(toCsv([["one", "1"], ["two", "1\r2"], ["three", "1\r2\r3"]])).toBe(
+      `one,1\ntwo,"1\r2"\nthree,"1\r2\r3"`,
+    );
+    expect(
+      toCsv([["one", "1"], ["two", "1\r\n2"], ["three", "1\r\n2\r\n3"]]),
+    ).toBe(`one,1\ntwo,"1\r\n2"\nthree,"1\r\n2\r\n3"`);
+  });
+
+  it("escapes properly if there are multiple special things", () => {
+    expect(
+      toCsv([
+        ["one", "with, comma"],
+        ["another", "with\nnewline"],
+        ["last", `with "quotes"`],
+      ]),
+    ).toBe(
+      `one,"with, comma"\nanother,"with\nnewline"\nlast,"with ""quotes"""`,
+    );
+  });
+
+  it("handles things that aren't strings", () => {
+    expect(
+      toCsv([
+        [undefined, null],
+        [true, false],
+        [1, 2, 3],
+        [{}, { hi: "there" }],
+      ]),
+    ).toBe(",\ntrue,false\n1,2,3\n[object Object],[object Object]");
+  });
+});

projects/s-js-utils/src/lib/to-csv.ts

@@ -0,0 +1,34 @@
+import { toString } from "micro-dash";
+
+/**
+ * Converts a 2D array to a csv string. Values are converted using micro-dash's toString().
+ *
+ * ```ts
+ * toCsv([["a", "b", "c"], ["d", "e", "f"], ["g", "h", "i"]]); // "a,b,c\nd,e,f\ng,h,i"
+ * toCsv([
+ *   ["a", "", "string"]
+ *   [undefined, null],
+ *   [true, false],
+ *   [1, 2, 3],
+     [{}, { hi: "there" }]
+ * ]) // "a,,string\n,\ntrue,false\n1,2,3\n[object Object],[object Object]"
+ * ```
+ */
+export function toCsv(content: any[][]) {
+  return content
+    .map((row) => row.map((cell) => toCellString(cell)).join(","))
+    .join("\n");
+}
+
+const specialCsvCharactersRegexp = /["|,|\n|\r]/;
+const allDoubleQuotes = /"/g;
+
+function toCellString(value: any) {
+  const string = toString(value);
+
+  if (specialCsvCharactersRegexp.test(string)) {
+    return `"${string.replace(allDoubleQuotes, `""`)}"`;
+  } else {
+    return string;
+  }
+}

projects/s-js-utils/src/public_api.ts

@@ -9,3 +9,4 @@ export * from "./lib/round-to-multiple-of";
 export * from "./lib/sleep";
 export * from "./lib/test-factory";
 export * from "./lib/time-utils";
+export * from "./lib/to-csv";

yarn.lock

@@ -4377,9 +4377,9 @@ methods@~1.1.2:
   version "1.1.2"
   resolved "https://registry.yarnpkg.com/methods/-/methods-1.1.2.tgz#5529a4d67654134edcc5266656835b0f851afcee"
 
-micro-dash@^4.1.0:
-  version "4.1.0"
-  resolved "https://registry.yarnpkg.com/micro-dash/-/micro-dash-4.1.0.tgz#6b69d9440d60ba83d6bc3295fa34ce4240936030"
+micro-dash@^4.2.0:
+  version "4.2.0"
+  resolved "https://registry.yarnpkg.com/micro-dash/-/micro-dash-4.2.0.tgz#84da0a853dc6a869cb365b7349518d1b4ed8548b"
   dependencies:
     tslib "^1.9.0"