File-content-replacer NPM

file-content-replacer

A file content replacer utility. Replaces contents within files, recursively within a directory.

Installation:

npm i file-content-replacer

Usage:

var fcr = require("file-content-replacer");

async function myFunc() {
    var result = await fcr(directoryPath, fileMatcher, replace, replaceWith, options).catch((err) => {
        console.log(err);
    });
    result && console.log(result.message);
    result && console.log(result.data);
}
myFunc();

/**
* 
* @param {*} directoryPath [type: string] - Path of the directory.
* @param {*} fileMatcher [type: function] - Predicate function for matching files.
* @param {*} replace [type: string|RegExp] - The substring to be replaced.
* @param {*} replaceWith [type: string|function] - The replacement which will replace the substring
* @param {?} options [type: Object] - Configuration object. This argument is OPTIONAL.
*
* return: Promise - The resolved object contains properties 'message' & 'data'.
*/

For the usage of replace and replaceWith parameters, the behavior is the same as String.prototype.replace:
(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/String/replace)

RegExp:
(https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/RegExp)

A complex example:

The below example describes a scenario wherein we want to update all the ".css" files in the current directory(recursive) and replace the text "/ASSETS/" with "assets/".

async function myFunc() {
    var result = await fcr(".", function (filepath) { return filepath.endsWith(".css"); }, /\/ASSETS\//gi, function (match, offset, string) {
        return match.toLowerCase().substr(1);
    }).catch((err) => {
        console.log(err);
    });
    result && console.log(result.message);
    result && console.log(result.data);
}
myFunc();

You can provide a directoryPath (i.e. first argument)
You can control the files to be matched via a fileMatcher (i.e. second argument) predicate function.
Note: If you want to lookup file(s) only at a specific directory, then use the filepath argument and return true with the appropriate comparison.
The predicate function gives you the flexibility to determine which exact file(s) should be matched.
Provide a string or RegExp as the replace (i.e. third argument) as in this case i.e. /\/ASSETS\//gi --> match global, case-insensitive occurences of the substring "/ASSETS/"
Provide a string or function as the replaceWith (i.e. fourth argument)
Additionally you can also provide a fifth argument options of type Object.
The valid properties in the options object are:
timeoutMillis - specify the timeout in milliseconds
e.g.: fcr(directoryPath, fileMatcher, replace, replaceWith, {timeoutMillis: 5000});
This would mean that if the replacement operation exceeds 5 seconds, then it will timeout.
The default value for timeoutMillis is 20000 i.e. 20 seconds and will be used if the options argument is missing or options.timeoutMillis is not specified.

A simple example:

The below example describes a scenario wherein we want to update all the ".css" files in the current directory(recursive) and replace the text "/assets/" with "assets/".

async function myFunc() {
    var result = await fcr(".", function (filepath) { return filepath.endsWith(".css"); }, "/assets/", "assets/").catch((err) => {
        console.log(err);
    });
    result && console.log(result.message);
    result && console.log(result.data);
}
myFunc();

In the above simple example, we will replace the substring "/assets/" with "assets/" in all the ".css" files in the current directory(recursive).
Note: Since we provided the third argument as a string and not a RegExp, it would only replace the first matching occurence in each file.
The purpose of this example is just to demonstrate the flexibility offered by the library.