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docs(csv): more examples for parse and CsvParseStream (#5605)

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This commit adds more examples to `parse` function and `CsvParseStream` class to
cover all the provided options.

Also fixes a few other things:

- Replace stale description `ParseError` with the correct `SyntaxError`.
- Fix the default value of `comment` property. The old comment says the default
  value is `#`, but this was wrong.
- Get negative value in `fieldsPerRecord` option working in `parse` as
  documented

---------

Co-authored-by: Asher Gomez <ashersaupingomez@gmail.com>
This commit is contained in:
Yusuke Tanaka 2024-08-02 13:24:15 +09:00 committed by GitHub
parent dd80d82961
commit b0f2088044
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GPG Key ID: B5690EEEBB952194
6 changed files with 498 additions and 61 deletions
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9
csv/_io.ts
View File

@ -45,7 +45,8 @@ export interface ReadOptions {
* If negative, no check is made and records may have a variable number of
* fields.
*
* If the wrong number of fields is in a row, a `ParseError` is thrown.
* If the wrong number of fields is in a row, a {@linkcode SyntaxError} is
* thrown.
*/
fieldsPerRecord?: number;
}
@ -227,11 +228,13 @@ export function createQuoteErrorMessage(
export function convertRowToObject(
row: string[],
headers: readonly string[],
index: number,
zeroBasedLine: number,
) {
if (row.length !== headers.length) {
throw new Error(
`Error number of fields line: ${index}\nNumber of fields found: ${headers.length}\nExpected number of fields: ${row.length}`,
`record on line ${
zeroBasedLine + 1
} has ${row.length} fields, but the header has ${headers.length} fields`,
);
}
const out: Record<string, unknown> = {};

2
csv/mod.ts
View File

@ -56,7 +56,9 @@
*
* results in
*
* ```ts no-assert
* [`the "word" is true`, `a "quoted-field"`]
* ```
*
* Newlines and commas may be included in a quoted-field
*

188
csv/parse.ts
View File

@ -208,7 +208,7 @@ class Parser {
this.#input = input.startsWith(BYTE_ORDER_MARK) ? input.slice(1) : input;
this.#cursor = 0;
const result: string[][] = [];
let _nbFields: number | undefined;
let lineResult: string[];
let first = true;
let lineIndex = 0;
@ -225,6 +225,25 @@ class Parser {
throw new Error("Invalid Delimiter");
}
// The number of fields per record that is either inferred from the first
// row (when options.fieldsPerRecord = 0), or set by the caller (when
// options.fieldsPerRecord > 0).
//
// Each possible variant means the following:
// "ANY": Variable number of fields is allowed.
// "UNINITIALIZED": The first row has not been read yet. Once it's read, the
// number of fields will be set.
// <number>: The number of fields per record that every record must follow.
let _nbFields: "ANY" | "UNINITIALIZED" | number;
if (options.fieldsPerRecord === undefined || options.fieldsPerRecord < 0) {
_nbFields = "ANY";
} else if (options.fieldsPerRecord === 0) {
_nbFields = "UNINITIALIZED";
} else {
// TODO: Should we check if it's a valid integer?
_nbFields = options.fieldsPerRecord;
}
while (true) {
const r = this.#parseRecord(lineIndex);
if (r === null) break;
@ -234,19 +253,15 @@ class Parser {
// the number of fields in the first record
if (first) {
first = false;
if (options.fieldsPerRecord !== undefined) {
if (options.fieldsPerRecord === 0) {
_nbFields = lineResult.length;
} else {
_nbFields = options.fieldsPerRecord;
}
if (_nbFields === "UNINITIALIZED") {
_nbFields = lineResult.length;
}
}
if (lineResult.length > 0) {
if (_nbFields && _nbFields !== lineResult.length) {
if (typeof _nbFields === "number" && _nbFields !== lineResult.length) {
throw new SyntaxError(
`record on line ${lineIndex}: wrong number of fields`,
`record on line ${lineIndex}: expected ${_nbFields} fields but got ${lineResult.length}`,
);
}
result.push(lineResult);
@ -269,7 +284,7 @@ export interface ParseOptions {
* are ignored. With leading whitespace the comment character becomes part of
* the field, even you provide `trimLeadingSpace: true`.
*
* @default {"#"}
* By default, no character is considered to be a start of a comment.
*/
comment?: string;
/** Flag to trim the leading space of the value.
@ -319,11 +334,25 @@ export interface ParseOptions {
* @example Usage
* ```ts
* import { parse } from "@std/csv/parse";
* import { assertEquals } from "@std/assert";
* import { assertEquals } from "@std/assert/equals";
*
* const string = "a,b,c\nd,e,f";
* const string = "a,b,c\n#d,e,f";
*
* assertEquals(parse(string), [["a", "b", "c"], ["d", "e", "f"]]);
* assertEquals(parse(string), [["a", "b", "c"], ["#d", "e", "f"]]);
* ```
*
* @example Quoted fields
* ```ts
* 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"]
* ]);
* ```
*
* @param input The input to parse.
@ -333,26 +362,139 @@ export function parse(input: string): string[][];
/**
* Parses CSV string into an array of objects or an array of arrays of strings.
*
* If `column` or `skipFirstRow` option is provided, it returns an array of
* If `columns` or `skipFirstRow` option is provided, it returns an array of
* objects, otherwise it returns an array of arrays of string.
*
* @example Usage
* @example Don't skip first row with `skipFirstRow: false`
* ```ts
* import { parse } from "@std/csv/parse";
* import { assertEquals } from "@std/assert";
* 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, { skipFirstRow: false });
*
* assertEquals(parse(string, { skipFirstRow: false }), [["a", "b", "c"], ["d", "e", "f"]]);
* assertEquals(parse(string, { skipFirstRow: true }), [{ a: "d", b: "e", c: "f" }]);
* assertEquals(parse(string, { columns: ["x", "y", "z"] }), [{ x: "a", y: "b", z: "c" }, { x: "d", y: "e", z: "f" }]);
* assertEquals(result, [["a", "b", "c"], ["d", "e", "f"]]);
* assertType<IsExact<typeof result, string[][]>>(true);
* ```
*
* @example Skip first row with `skipFirstRow: true`
* ```ts
* 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, { skipFirstRow: true });
*
* assertEquals(result, [{ a: "d", b: "e", c: "f" }]);
* assertType<IsExact<typeof result, Record<string, string | undefined>[]>>(true);
* ```
*
* @example Specify columns with `columns` option
* ```ts
* 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 Specify columns with `columns` option and skip first row with
* `skipFirstRow: true`
* ```ts
* 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"], 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"`
* ```ts
* 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`
* ```ts
* 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`
* ```ts
* 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
* ```ts
* 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`
* ```ts
* 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,
* "record on line 2: expected 2 fields but got 3",
* );
* ```
*
* @example Enforce the number of fields for each row with `fieldsPerRecord: 2`
* ```ts
* 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,
* "record on line 2: expected 2 fields but got 3",
* );
* ```
*
* @typeParam T The options' type for parsing.
* @param input The input to parse.
* @param options The options for parsing.
* @returns If you don't provide `options.skipFirstRow` and `options.columns`, it returns `string[][]`.
* If you provide `options.skipFirstRow` or `options.columns`, it returns `Record<string, unknown>[]`.
* @returns 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>[]`.
*/
export function parse<const T extends ParseOptions>(
input: string,
@ -378,9 +520,9 @@ export function parse<const T extends ParseOptions>(
headers = options.columns;
}
const firstLineIndex = options.skipFirstRow ? 1 : 0;
const zeroBasedFirstLineIndex = options.skipFirstRow ? 1 : 0;
return r.map((row, i) => {
return convertRowToObject(row, headers, firstLineIndex + i);
return convertRowToObject(row, headers, zeroBasedFirstLineIndex + i);
}) as ParseResult<ParseOptions, T>;
}
return r as ParseResult<ParseOptions, T>;

274
csv/parse_stream.ts
View File

@ -23,7 +23,7 @@ export interface CsvParseStreamOptions {
* are ignored. With leading whitespace the comment character becomes part of
* the field, even you provide `trimLeadingSpace: true`.
*
* @default {"#"}
* By default, no character is considered to be a start of a comment.
*/
comment?: string;
/** Flag to trim the leading space of the value.
@ -49,8 +49,8 @@ export interface CsvParseStreamOptions {
* If negative, no check is made and records may have a variable number of
* fields.
*
* If the wrong number of fields is in a row, a {@linkcode ParseError} is
* thrown.
* If the wrong number of fields is in a row, a {@linkcode https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/SyntaxError | SyntaxError}
* is thrown.
*/
fieldsPerRecord?: number;
/**
@ -108,17 +108,233 @@ export type RowType<T> = T extends undefined ? string[]
* A `CsvParseStream` expects input conforming to
* {@link https://www.rfc-editor.org/rfc/rfc4180.html | RFC 4180}.
*
* @example Usage
* ```ts no-assert
* @example Usage with default options
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
* import { assertType, IsExact } from "@std/testing/types"
*
* const source = ReadableStream.from([
* "name,age",
* "Alice,34",
* "Bob,24",
* "Charlie,45",
* "name,age\n",
* "Alice,34\n",
* "Bob,24\n",
* ]);
* const parts = source.pipeThrough(new CsvParseStream());
* const stream = source.pipeThrough(new CsvParseStream());
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [
* ["name", "age"],
* ["Alice", "34"],
* ["Bob", "24"],
* ]);
* assertType<IsExact<typeof result, string[][]>>(true);
* ```
*
* @example Skip first row with `skipFirstRow: true`
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
* import { assertType, IsExact } from "@std/testing/types"
*
* const source = ReadableStream.from([
* "name,age\n",
* "Alice,34\n",
* "Bob,24\n",
* ]);
* const stream = source.pipeThrough(new CsvParseStream({ skipFirstRow: true }));
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [
* { name: "Alice", age: "34" },
* { name: "Bob", age: "24" },
* ]);
* assertType<IsExact<typeof result, Record<string, string | undefined>[]>>(true);
* ```
*
* @example Specify columns with `columns` option
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
* import { assertType, IsExact } from "@std/testing/types"
*
* const source = ReadableStream.from([
* "Alice,34\n",
* "Bob,24\n",
* ]);
* const stream = source.pipeThrough(new CsvParseStream({
* columns: ["name", "age"]
* }));
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [
* { name: "Alice", age: "34" },
* { name: "Bob", age: "24" },
* ]);
* assertType<IsExact<typeof result, Record<"name" | "age", string>[]>>(true);
* ```
*
* @example Specify columns with `columns` option and skip first row with
* `skipFirstRow: true`
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
* import { assertType, IsExact } from "@std/testing/types"
*
* const source = ReadableStream.from([
* "Alice,34\n",
* "Bob,24\n",
* ]);
* const stream = source.pipeThrough(new CsvParseStream({
* columns: ["name", "age"],
* skipFirstRow: true,
* }));
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [{ name: "Bob", age: "24" }]);
* assertType<IsExact<typeof result, Record<"name" | "age", string>[]>>(true);
* ```
*
* @example TSV (tab-separated values) with `separator: "\t"`
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
*
* const source = ReadableStream.from([
* "Alice\t34\n",
* "Bob\t24\n",
* ]);
* const stream = source.pipeThrough(new CsvParseStream({
* separator: "\t",
* }));
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [
* ["Alice", "34"],
* ["Bob", "24"],
* ]);
* ```
*
* @example Trim leading space with `trimLeadingSpace: true`
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
*
* const source = ReadableStream.from([
* " Alice,34\n ",
* "Bob, 24\n",
* ]);
* const stream = source.pipeThrough(new CsvParseStream({
* trimLeadingSpace: true,
* }));
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [
* ["Alice", "34"],
* ["Bob", "24"],
* ]);
* ```
*
* @example Quoted fields
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
*
* const source = ReadableStream.from([
* `"a ""word""","com`,
* `ma,","newline`,
* `\n"\nfoo,bar,b`,
* `az\n`,
* ]);
* const stream = source.pipeThrough(new CsvParseStream());
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [
* ['a "word"', "comma,", "newline\n"],
* ["foo", "bar", "baz"]
* ]);
* ```
*
* @example Allow lazy quotes with `lazyQuotes: true`
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
*
* const source = ReadableStream.from([
* `a "word","1"`,
* `2",a","b`,
* ]);
* const stream = source.pipeThrough(new CsvParseStream({
* lazyQuotes: true,
* }));
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [['a "word"', '1"2', 'a"', 'b']]);
* ```
*
* @example Define comment prefix with `comment` option
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
*
* const source = ReadableStream.from([
* "Alice,34\n",
* "# THIS IS A COMMENT\n",
* "Bob,24\n",
* ]);
* const stream = source.pipeThrough(new CsvParseStream({
* comment: "#",
* }));
* const result = await Array.fromAsync(stream);
*
* assertEquals(result, [
* ["Alice", "34"],
* ["Bob", "24"],
* ]);
* ```
*
* @example Infer the number of fields from the first row with
* `fieldsPerRecord: 0`
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
* import { assertRejects } from "@std/assert/rejects";
*
* const source = ReadableStream.from([
* "Alice,34\n",
* "Bob,24,CA\n", // Note that this row has more fields than the first row
* ]);
* const stream = source.pipeThrough(new CsvParseStream({
* fieldsPerRecord: 0,
* }));
* const reader = stream.getReader();
* assertEquals(await reader.read(), { done: false, value: ["Alice", "34"] });
* await assertRejects(
* () => reader.read(),
* SyntaxError,
* "record on line 2: expected 2 fields but got 3",
* );
* ```
*
* @example Enforce the number of field for each row with `fieldsPerRecord: 2`
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
* import { assertRejects } from "@std/assert/rejects";
*
* const source = ReadableStream.from([
* "Alice,34\n",
* "Bob,24,CA\n",
* ]);
* const stream = source.pipeThrough(new CsvParseStream({
* fieldsPerRecord: 2,
* }));
* const reader = stream.getReader();
* assertEquals(await reader.read(), { done: false, value: ["Alice", "34"] });
* await assertRejects(
* () => reader.read(),
* SyntaxError,
* "record on line 2: expected 2 fields but got 3",
* );
* ```
*
* @typeParam T The type of options for the stream.
@ -258,20 +474,21 @@ export class CsvParseStream<
* The instance's {@linkcode ReadableStream}.
*
* @example Usage
* ```ts no-assert
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
*
* const source = ReadableStream.from([
* "name,age",
* "Alice,34",
* "Bob,24",
* "Charlie,45",
* "name,age\n",
* "Alice,34\n",
* "Bob,24\n",
* ]);
* const parseStream = new CsvParseStream();
* const parseStream = new CsvParseStream({ skipFirstRow: true });
* const parts = source.pipeTo(parseStream.writable);
* for await (const part of parseStream.readable) {
* console.log(part);
* }
* assertEquals(await Array.fromAsync(parseStream.readable), [
* { name: "Alice", age: "34" },
* { name: "Bob", age: "24" },
* ]);
* ```
*
* @returns The instance's {@linkcode ReadableStream}.
@ -284,20 +501,21 @@ export class CsvParseStream<
* The instance's {@linkcode WritableStream}.
*
* @example Usage
* ```ts no-assert
* ```ts
* import { CsvParseStream } from "@std/csv/parse-stream";
* import { assertEquals } from "@std/assert/equals";
*
* const source = ReadableStream.from([
* "name,age",
* "Alice,34",
* "Bob,24",
* "Charlie,45",
* "name,age\n",
* "Alice,34\n",
* "Bob,24\n",
* ]);
* const parseStream = new CsvParseStream();
* const parseStream = new CsvParseStream({ skipFirstRow: true });
* const parts = source.pipeTo(parseStream.writable);
* for await (const part of parseStream.readable) {
* console.log(part);
* }
* assertEquals(await Array.fromAsync(parseStream.readable), [
* { name: "Alice", age: "34" },
* { name: "Bob", age: "24" },
* ]);
* ```
*
* @returns The instance's {@linkcode WritableStream}.

15
csv/parse_stream_test.ts
View File

@ -350,14 +350,23 @@ x,,,
columns: ["foo", "bar", "baz"],
},
{
name: "mismatching number of headers and fields",
name: "mismatching number of headers and fields 1",
input: "a,b,c\nd,e",
skipFirstRow: true,
columns: ["foo", "bar", "baz"],
error: {
klass: Error,
msg:
"Error number of fields line: 1\nNumber of fields found: 3\nExpected number of fields: 2",
msg: "record on line 2 has 2 fields, but the header has 3 fields",
},
},
{
name: "mismatching number of headers and fields 2",
input: "a,b,c\nd,e,,g",
skipFirstRow: true,
columns: ["foo", "bar", "baz"],
error: {
klass: Error,
msg: "record on line 2 has 4 fields, but the header has 3 fields",
},
},
{

71
csv/parse_test.ts
View File

@ -23,6 +23,7 @@ Deno.test({
);
},
});
await t.step({
name: "CRLF",
fn() {
@ -97,6 +98,42 @@ Deno.test({
},
});
await t.step({
name: "BlankField",
fn() {
const input = "a,b,c\nd,,f";
assertEquals(
parse(input),
[["a", "b", "c"], ["d", "", "f"]],
);
},
});
await t.step({
name: "BlankField2",
fn() {
const input = "a,b,c\nd,,f";
assertEquals(
parse(input, { skipFirstRow: true }),
[{ a: "d", b: "", c: "f" }],
);
},
});
await t.step({
name: "BlankField3",
fn() {
const input = "a,b,c\nd,,f";
assertEquals(
parse(input, { columns: ["one", "two", "three"] }),
[
{ one: "a", two: "b", three: "c" },
{ one: "d", two: "", three: "f" },
],
);
},
});
await t.step({
name: "BlankLine",
fn() {
@ -257,7 +294,7 @@ Deno.test({
assertThrows(
() => parse(input, { fieldsPerRecord: 0 }),
SyntaxError,
"record on line 2: wrong number of fields",
"record on line 2: expected 3 fields but got 2",
);
},
});
@ -268,10 +305,21 @@ Deno.test({
assertThrows(
() => parse(input, { fieldsPerRecord: 2 }),
SyntaxError,
"record on line 1: wrong number of fields",
"record on line 1: expected 2 fields but got 3",
);
},
});
await t.step({
name: "NegativeFieldsPerRecord",
fn() {
const input = `a,b,c\nd,e`;
const output = [
["a", "b", "c"],
["d", "e"],
];
assertEquals(parse(input, { fieldsPerRecord: -1 }), output);
},
});
await t.step({
name: "FieldCount",
fn() {
@ -783,7 +831,7 @@ c"d,e`;
},
});
await t.step({
name: "mismatching number of headers and fields",
name: "mismatching number of headers and fields 1",
fn() {
const input = "a,b,c\nd,e";
assertThrows(
@ -793,7 +841,22 @@ c"d,e`;
columns: ["foo", "bar", "baz"],
}),
Error,
"Error number of fields line: 1\nNumber of fields found: 3\nExpected number of fields: 2",
"record on line 2 has 2 fields, but the header has 3 fields",
);
},
});
await t.step({
name: "mismatching number of headers and fields 2",
fn() {
const input = "a,b,c\nd,e,,g";
assertThrows(
() =>
parse(input, {
skipFirstRow: true,
columns: ["foo", "bar", "baz"],
}),
Error,
"record on line 2 has 4 fields, but the header has 3 fields",
);
},
});