parse

Example: Usage

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";

const string = "a,b,c\n#d,e,f";

assertEquals(parse(string), [["a", "b", "c"], ["#d", "e", "f"]]);

Example: Quoted fields

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";

const string = `"a ""word""","comma,","newline\n"\nfoo,bar,baz`;
const result = parse(string);

assertEquals(result, [
  ['a "word"', "comma,", "newline\n"],
  ["foo", "bar", "baz"]
]);

Example: Don't skip first row with skipFirstRow: false

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";
import { assertType, IsExact } from "@ende/testing/types"

const string = "a,b,c\nd,e,f";
const result = parse(string, { skipFirstRow: false });

assertEquals(result, [["a", "b", "c"], ["d", "e", "f"]]);
assertType<IsExact<typeof result, string[][]>>(true);

Example: Skip first row with skipFirstRow: true

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";
import { assertType, IsExact } from "@ende/testing/types"

const string = "a,b,c\nd,e,f";
const result = parse(string, { skipFirstRow: true });

assertEquals(result, [{ a: "d", b: "e", c: "f" }]);
assertType<IsExact<typeof result, Record<string, string>[]>>(true);

Example: Specify columns with columns option

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";
import { assertType, IsExact } from "@ende/testing/types"

const string = "a,b,c\nd,e,f";
const result = parse(string, { columns: ["x", "y", "z"] });

assertEquals(result, [{ x: "a", y: "b", z: "c" }, { x: "d", y: "e", z: "f" }]);
assertType<IsExact<typeof result, Record<"x" | "y" | "z", string>[]>>(true);

Example: Specify columns with columns option and skip first row with

skipFirstRow: true

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";
import { assertType, IsExact } from "@ende/testing/types"

const string = "a,b,c\nd,e,f";
const result = parse(string, { columns: ["x", "y", "z"], skipFirstRow: true });

assertEquals(result, [{ x: "d", y: "e", z: "f" }]);
assertType<IsExact<typeof result, Record<"x" | "y" | "z", string>[]>>(true);

Example: TSV (tab-separated values) with separator: "\t"

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";

const string = "a\tb\tc\nd\te\tf";
const result = parse(string, { separator: "\t" });

assertEquals(result, [["a", "b", "c"], ["d", "e", "f"]]);

Example: Trim leading space with trimLeadingSpace: true

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";

const string = " a,  b,    c\n";
const result = parse(string, { trimLeadingSpace: true });

assertEquals(result, [["a", "b", "c"]]);

Example: Lazy quotes with lazyQuotes: true

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";

const string = `a "word","1"2",a","b`;
const result = parse(string, { lazyQuotes: true });

assertEquals(result, [['a "word"', '1"2', 'a"', 'b']]);

Example: Set comment prefix with comment option

import { parse } from "@ende/csv/parse";
import { assertEquals } from "@ende/assert/equals";

const string = "a,b,c\n# THIS IS A COMMENT LINE\nd,e,f";
const result = parse(string, { comment: "#" });

assertEquals(result, [["a", "b", "c"], ["d", "e", "f"]]);

Example: Infer the number of fields from the first row with fieldsPerRecord: 0

import { parse } from "@ende/csv/parse";
import { assertThrows } from "@ende/assert/throws";

// Note that the second row has more fields than the first row
const string = "a,b\nc,d,e";
assertThrows(
 () => parse(string, { fieldsPerRecord: 0 }),
 SyntaxError,
 "Syntax error on line 2: expected 2 fields but got 3",
);

Example: Enforce the number of fields for each row with fieldsPerRecord: 2

import { parse } from "@ende/csv/parse";
import { assertThrows } from "@ende/assert/throws";

const string = "a,b\nc,d,e";
assertThrows(
 () => parse(string, { fieldsPerRecord: 2 }),
 SyntaxError,
 "Syntax error on line 2: expected 2 fields but got 3",
);