deno.land / std@0.139.0 / encoding / csv.ts

// Ported from Go:// https://github.com/golang/go/blob/go1.12.5/src/encoding/csv/// Copyright 2011 The Go Authors. All rights reserved. BSD license.// https://github.com/golang/go/blob/master/LICENSE// Copyright 2018-2022 the Deno authors. All rights reserved. MIT license.
import { BufReader } from "../io/buffer.ts";import { TextProtoReader } from "../textproto/mod.ts";import { StringReader } from "../io/readers.ts";import { assert } from "../_util/assert.ts";import { ERR_FIELD_COUNT, ERR_INVALID_DELIM, ParseError, readRecord,} from "./csv/_io.ts";import type { LineReader, ReadOptions } from "./csv/_io.ts";
export { ERR_BARE_QUOTE, ERR_FIELD_COUNT, ERR_INVALID_DELIM, ERR_QUOTE, ParseError,} from "./csv/_io.ts";export type { ReadOptions } from "./csv/_io.ts";export { NEWLINE, stringify, StringifyError } from "./csv_stringify.ts";
export type { Column, ColumnDetails, DataItem, StringifyOptions,} from "./csv_stringify.ts";
class TextProtoLineReader implements LineReader { #tp: TextProtoReader; constructor(bufReader: BufReader) { this.#tp = new TextProtoReader(bufReader); }
async readLine() { let line: string; const r = await this.#tp.readLine(); if (r === null) return null; line = r;
// For backwards compatibility, drop trailing \r before EOF. if ( (await this.isEOF()) && line.length > 0 && line[line.length - 1] === "\r" ) { line = line.substring(0, line.length - 1); }
// Normalize \r\n to \n on all input lines. if ( line.length >= 2 && line[line.length - 2] === "\r" && line[line.length - 1] === "\n" ) { line = line.substring(0, line.length - 2); line = line + "\n"; }
return line; }
async isEOF() { return (await this.#tp.r.peek(0)) === null; }}
const INVALID_RUNE = ["\r", "\n", '"'];
function chkOptions(opt: ReadOptions): void { if (!opt.separator) { opt.separator = ","; } if (!opt.trimLeadingSpace) { opt.trimLeadingSpace = false; } if ( INVALID_RUNE.includes(opt.separator) || (typeof opt.comment === "string" && INVALID_RUNE.includes(opt.comment)) || opt.separator === opt.comment ) { throw new Error(ERR_INVALID_DELIM); }}
/** * Parse the CSV from the `reader` with the options provided and return `string[][]`. * * @param reader provides the CSV data to parse * @param opt controls the parsing behavior */export async function readMatrix( reader: BufReader, opt: ReadOptions = { separator: ",", trimLeadingSpace: false, lazyQuotes: false, },): Promise<string[][]> { const result: string[][] = []; let _nbFields: number | undefined; let lineResult: string[]; let first = true; let lineIndex = 0; chkOptions(opt);
const lineReader = new TextProtoLineReader(reader); for (;;) { const r = await readRecord(lineIndex, lineReader, opt); if (r === null) break; lineResult = r; lineIndex++; // If fieldsPerRecord is 0, Read sets it to // the number of fields in the first record if (first) { first = false; if (opt.fieldsPerRecord !== undefined) { if (opt.fieldsPerRecord === 0) { _nbFields = lineResult.length; } else { _nbFields = opt.fieldsPerRecord; } } }
if (lineResult.length > 0) { if (_nbFields && _nbFields !== lineResult.length) { throw new ParseError(lineIndex, lineIndex, null, ERR_FIELD_COUNT); } result.push(lineResult); } } return result;}
/** * Parse the CSV string/buffer with the options provided. * * ColumnOptions provides the column definition * and the parse function for each entry of the * column. */export interface ColumnOptions { /** * Name of the column to be used as property */ name: string;}
export interface ParseOptions extends ReadOptions { /** * If you provide `skipFirstRow: true` and `columns`, the first line will be skipped. * If you provide `skipFirstRow: true` but not `columns`, the first line will be skipped and used as header definitions. */ skipFirstRow?: boolean;
/** * If you provide `string[]` or `ColumnOptions[]`, those names will be used for header definition. */ columns?: string[] | ColumnOptions[];}
/** * Csv parse helper to manipulate data. * Provides an auto/custom mapper for columns. * @param input Input to parse. Can be a string or BufReader. * @param opt options of the parser. * @returns If you don't provide `opt.skipFirstRow` and `opt.columns`, it returns `string[][]`. * If you provide `opt.skipFirstRow` or `opt.columns`, it returns `Record<string, unkown>[]`. */export async function parse( input: string | BufReader,): Promise<string[][]>;export async function parse( input: string | BufReader, opt: Omit<ParseOptions, "columns" | "skipFirstRow">,): Promise<string[][]>;export async function parse( input: string | BufReader, opt: Omit<ParseOptions, "columns"> & { columns: string[] | ColumnOptions[]; },): Promise<Record<string, unknown>[]>;export async function parse( input: string | BufReader, opt: Omit<ParseOptions, "skipFirstRow"> & { skipFirstRow: true; },): Promise<Record<string, unknown>[]>;export async function parse( input: string | BufReader, opt: ParseOptions,): Promise<string[][] | Record<string, unknown>[]>;export async function parse( input: string | BufReader, opt: ParseOptions = { skipFirstRow: false, },): Promise<string[][] | Record<string, unknown>[]> { let r: string[][]; if (input instanceof BufReader) { r = await readMatrix(input, opt); } else { r = await readMatrix(new BufReader(new StringReader(input)), opt); } if (opt.skipFirstRow || opt.columns) { let headers: ColumnOptions[] = []; let i = 0;
if (opt.skipFirstRow) { const head = r.shift(); assert(head != null); headers = head.map( (e): ColumnOptions => { return { name: e, }; }, ); i++; }
if (opt.columns) { if (typeof opt.columns[0] !== "string") { headers = opt.columns as ColumnOptions[]; } else { const h = opt.columns as string[]; headers = h.map( (e): ColumnOptions => { return { name: e, }; }, ); } }
return r.map((e) => { if (e.length !== headers.length) { throw `Error number of fields line:${i}`; } i++; const out: Record<string, unknown> = {}; for (let j = 0; j < e.length; j++) { out[headers[j].name] = e[j]; } return out; }); } return r;}
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