browser-line-reader - npm Package Compare versions

Comparing version 0.2.0 to 0.3.0

.eslintrc.js

@@ -5,3 +5,3 @@ module.exports = {
 		'plugin:@typescript-eslint/recommended', // Uses the recommended rules from the @typescript-eslint/eslint-plugin
-		'prettier/@typescript-eslint', // Uses eslint-config-prettier to disable ESLint rules from @typescript-eslint/eslint-plugin that would conflict with prettier
+		'prettier', // Uses eslint-config-prettier to disable ESLint rules from @typescript-eslint/eslint-plugin that would conflict with prettier
 		'plugin:prettier/recommended', // Enables eslint-plugin-prettier and displays prettier errors as ESLint errors. Make sure this is always the last configuration in the extends array.
@@ -8,0 +8,0 @@ ],

.prettierrc.js

@@ -1,10 +0,6 @@
-module.exports =  {
+module.exports = {
 	semi: true,
 	trailingComma: 'es5',
 	singleQuote: true,
-	printWidth: 120,
-	tabWidth: 4,
-	useTabs: true,
-	endOfLine: 'lf',
 	arrowParens: 'always',
 };

package.json

 {
 	"name": "browser-line-reader",
-	"version": "0.2.0",
+	"version": "0.3.0",
 	"description": "A line by line async file reader for the browser",
@@ -10,4 +10,7 @@ "main": "./src/index.js",
 		"build": "tsc",
-		"prepare": "npm run build"
+		"prepare": "husky install && npm run build"
 	},
+	"engines": {
+		"node": ">= 12.22"
+	},
 	"repository": {
@@ -32,28 +35,22 @@ "type": "git",
 	"devDependencies": {
-		"@types/jest": "^26.0.9",
-		"@typescript-eslint/eslint-plugin": "^3.8.0",
-		"@typescript-eslint/parser": "^3.8.0",
-		"eslint": "^7.6.0",
-		"eslint-config-prettier": "^6.11.0",
-		"eslint-plugin-prettier": "^3.1.4",
-		"husky": "^4.2.5",
-		"jest": "^26.3.0",
-		"lint-staged": "^10.2.11",
-		"prettier": "^2.0.5",
-		"ts-jest": "^26.1.4",
-		"typescript": "^3.9.7"
+		"@types/jest": "^29.2.3",
+		"@typescript-eslint/eslint-plugin": "^5.44.0",
+		"@typescript-eslint/parser": "^5.44.0",
+		"eslint": "^8.28.0",
+		"eslint-config-prettier": "^8.5.0",
+		"eslint-plugin-prettier": "^4.2.1",
+		"husky": "^8.0.2",
+		"jest": "^29.3.1",
+		"jest-environment-jsdom": "^29.3.1",
+		"lint-staged": "^13.0.3",
+		"ls-engines": "^0.7.0",
+		"prettier": "^2.8.0",
+		"ts-jest": "^29.0.3",
+		"typescript": "^4.9.3"
 	},
-	"husky": {
-		"hooks": {
-			"pre-commit": "lint-staged"
-		}
-	},
 	"lint-staged": {
-		"*.ts": [
+		"*.{js,ts}": [
 			"eslint --fix",
+			"prettier --write",
 			"git add"
-		],
-		"*.js": [
-			"eslint --fix",
-			"git add"
 		]
@@ -63,14 +60,11 @@ },
 		"transform": {
-			"^.+\\.tsx?$": "ts-jest"
+			"^.+\\.ts$": "ts-jest"
 		},
-		"testRegex": "(/__tests__/.*|(\\.|/)(test|spec))\\.(jsx?|tsx?)$",
+		"testRegex": "./tests/.*\\.spec\\.ts$",
 		"moduleFileExtensions": [
 			"ts",
-			"tsx",
-			"js",
-			"jsx",
-			"json",
-			"node"
-		]
+			"js"
+		],
+		"testEnvironment": "jsdom"
 	}
 }

README.md

 # browser-line-reader
 An asynchronous line by line file reader for the browser.
 
-This is a project I have been working on since I have found
-the lack of asynchronous, promise aware, typescript based file reader
-solutions lacking when it comes to the browser.
+This project addresses the lack of asynchronous, promise aware, typescript based file reader solutions specifically
+crafted for the browser.
 
-This module is designed to read a File object, using the standard
-FileReader, one line at a time. In order to achieve this, the file is
-actually subject to multiple reads, in "chunks", which can contain
-any number of lines.
+This module reads a `File` object, using the standard `FileReader`, one line at a time.
+In order to achieve this, the file is subject to multiple reads, in 'chunks', which can contain any number of lines.
 
-What this means is that there is no need for the entire file to be stored
-in browser memory, and lines can be processed and then discarded. I find
-that this is especially useful when reading in large files spanning many
-hundreds of megabytes.
+The advantage of this method is that there is no need for the entire file to be stored in browser memory,
+and lines can be processed and then discarded.
+This is especially useful when reading in large files spanning many hundreds of megabytes.
 
@@ -24,13 +20,39 @@ ## Installation
 ## Usage
+The following types are used in the type signatures below:
 
-Currently, there is only one function accessible, ```readLines```,
-which will read all the lines of a file, one by one. The usage
-can be described by the below code example:
+```typescript
+interface Options {
+	encoding?: string;
+}
 
+type LineReaderCallback = (line: string) => void;
+```
+
+To get started, import the `LineReader` class as a default export.
+
 ```typescript
 import LineReader from 'browser-line-reader';
+```
+
+### constructor
+Type: `(file: File) => LineReader`
+
+The `LineReader` class constructor accepting the File object to read.
+
+
+```typescript
 const myFile: File = new File(['My name is...'], 'SlimShady');
 const lineReader: LineReader = new LineReader(myFile);
+```
+
+### readLines
+Type: `(callback?: LineReaderCallback) => Promise<number>`
+
+Read all the lines of a file, one by one.
+Accepts a callback with one parameter of type `string`, which is the line just read.
+Returns a promise containing the total number of lines read.
+Throws an error passed through from the internal `FileReader.prototype.onerror` event.
+
+```typescript
 lineReader.readLines((line: string) => {
-	// Efficiently store this line in a good data structure
 	console.log(line);
@@ -44,20 +66,22 @@ }).then((numLinesRead: number) => {
 
-- The line reader accepts one argument of type ```File```,
-which is the File object to read.
-- The ```readLines``` function accepts a callback with
-one parameter of type ```string```, which is the line just read.
-- The ```readLines``` function returns a promise with return type
-```Promise<number|string>```, where on success, the total number of
-lines read is returned, and on failure, an error message.
+### readNLines
+Type: `(nLines: number, callback?: LineReaderCallback) => Promise<number>`
 
-## TODO
+Read the first `n` lines of a file of `k` lines, or all lines if `n > k` or `n < 0`.
+Return and exceptions are identical to `Linereader.prototype.readLines`.
 
-There are a number of items I would still like to implement.
-This list is growing and feel free to send me suggestions if you
-find this tool useful.
+```typescript
+lineReader.readNLines(10, (line: string) => {
+	console.log(line);
+});
+```
 
+## Missing Features
+
 - Support for different kinds of line separators
 - Support for separate read header action
-- Support for reading a certain number of lines
 - Efficiency optimisations
-- Benchmarking against standard FileReader API
+- Benchmarking against standard FileReader API
+- Add contributing guidelines
+
+Please suggest or implement these or any other features you feel are missing.

src/index.js

@@ -5,4 +5,4 @@ "use strict";
     function LineReader(file, options) {
+        if (options === void 0) { options = { encoding: 'UTF-8' }; }
         var _this = this;
-        if (options === void 0) { options = { encoding: 'UTF-8' }; }
         this.fileReader = new FileReader();
@@ -19,2 +19,5 @@ this.readPosition = 0;
     LineReader.prototype.readLines = function (callback) {
+        return this.readNLines(-1, callback);
+    };
+    LineReader.prototype.readNLines = function (nLines, callback) {
         var _this = this;
@@ -25,9 +28,12 @@ var count = 0;
                 var size = lines.length;
-                if (typeof callback === 'function') {
-                    var index = -1;
-                    while (++index < size) {
+                var index = -1;
+                while (++index < size && (count < nLines || nLines < 0)) {
+                    count++;
+                    if (typeof callback === 'function') {
                         callback(lines[index]);
                     }
                 }
-                count += size;
+                if (count === nLines) {
+                    _this.emit('end');
+                }
                 _this.step();
@@ -34,0 +40,0 @@ });

src/interfaces.ts

 export interface Options {
 	encoding?: string;
 }
+
+export type LineReaderCallback = (line: string) => void;

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Improved metrics

Total package byte prevSize

13800

increased by6.51%

Number of package files

13

increased by8.33%

Lines of code

137

increased by2.24%

Number of lines in readme file

86

increased by40.98%

Worsened metrics

Dev dependency count

14

increased by16.67%

No dependency changes