Function parse

  • parse(input): string[][]

  • Parses CSV string into an array of arrays of strings.

    Parameters

    • input: string

      The input to parse.

    Returns string[][]

    The parsed data.

    Example: Usage

    import { parse } from "@std/csv/parse";
    import { assertEquals } from "@std/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 "@std/csv/parse";
    import { assertEquals } from "@std/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"]
    ]);
  • parse<const T>(input, options): ParseResult<ParseOptions, T>

  • Parses CSV string into an array of objects or an array of arrays of strings.

    If columns or skipFirstRow option is provided, it returns an array of objects, otherwise it returns an array of arrays of string.

    Type Parameters

    Parameters

    • input: string

      The input to parse.

    • options: T

      The options for parsing.

    Returns ParseResult<ParseOptions, T>

    If you don't provide options.skipFirstRow or options.columns, it returns string[][]. If you provide options.skipFirstRow or options.columns, it returns Record<string, string>[].

    Example: Specify columns with `columns` option

    import { parse } from "@std/csv/parse";
    import { assertEquals } from "@std/assert/equals";
    import { assertType, IsExact } from "@std/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: TSV (tab-separated values) with `separator: "\t"`

    import { parse } from "@std/csv/parse";
    import { assertEquals } from "@std/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 "@std/csv/parse";
    import { assertEquals } from "@std/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 "@std/csv/parse";
    import { assertEquals } from "@std/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 "@std/csv/parse";
    import { assertEquals } from "@std/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 "@std/csv/parse";
    import { assertThrows } from "@std/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 "@std/csv/parse";
    import { assertThrows } from "@std/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",
    );

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