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Node.js Articles
Page 17 of 22
pathExists() function in fs-extra - NodeJS
Introduction to Async pathExists()This method will test whether the given path exists or not by checking with the file system. It will throw error in callback if the path does not exist.SyntaxpathExists(file[, callback])Parametersfile – This is the path of the file that needs to be checked in all the file systems.callback – This function will give a callback if any error occurs.ExampleCheck that fs-extra is installed before proceeding; if not, install fs-exra.You can use the following command to check whether fs-extra is installed or not.npm ls fs-extraCreate a pathExists.js and copy-paste the following code snippet into that file.Now, run the ...
Read MoreoutputFile() function in fs-extra - NodeJS
Introduction to Async outputFile()This method is similar to write file of 'fs'. The only difference is it will create the parent directories, if not present. The argument passed should always be a file path, not a buffer or a file descriptor.SyntaxoutputFile(file, data[, options] [, callback])Parametersfile – String parameter which will contain name and location of the file.data – The data can hold a string data, buffer stream or a Unit8 string array that is to be stored.options – The 'outputFile' function supports the following options −encoding – Default 'utf8'.mode – Default 0o666signal – allown aborting an ongoing output file functioncallback ...
Read MoreNodeJS - Exception Handling in Asynchronous Code
An exception is a type of an event that occurs while executing or running a program that stops the normal flow of the program and returns to the system. When an exception occurs the method creates an object and gives it to the runtime system. This creating an exception and giving it to the runtime system is known as throwing an Exception.We need to handle these Exceptions to handle any use case and prevent the system from crashing or performing an unprecedented set of instructions. If we donot handle or throw exceptions, the program may perform strangely.Exception handling in Asynchronous ...
Read MoreHow to overlay text on an image using JIMP in NodeJS?
Like Image, we can also overlay text on an image using JIMP. This can be used to display brands or copyright information on images. The print() method is used to write text on images. Though Jimp can only support the Bitmap font format (.fnt), but other fonts can be converted into this format to be compatible and used with JIMP.Syntaximage.print(font, x, y, message);Definition of print() paramtersfont – This describes the font passed by the user for writing the text on image.x, y – The coordinates where the file will be placed.message – This is the user defined message which is passed in ...
Read MoreHow to apply a Sepia tone to an image in Node Jimp?
NodeJS – Sepia() is an inbuilt function that is used to apply a sepia or wash tone to the image.Syntaxsepia(cb)sepia() paramterscb – This is an optional parameter that can be invoked after the compilation is complete.Input ImageUsing Node JIMP – SEPIA()Before proceeding to use sepia() functions, please check that the following statements are already executed for setting up the environment.npm init -y // Initialising the Node environmentnpm install jimp --save // Installing the jimp dependencyCreate a sepia.js file and copy-paste the following code snippet in it.Use node sepia.js to run the code.Note: – The method name should match with the JS ...
Read MoreHow to rotate an image in Node Jimp?
NodeJS – Rotate() is an inbuilt function that is used to rotate the images. The image is rotated clockwise where the dimensions of the image remains same and no changes are made on them.Syntaxrotate ( r, mode, cb )Definition of rotate() paramtersr – Used to store the rotation angle at which the image will be rotated.mode – Used to store the scaling method of the image. This is an optional parameter.cb – This is an optional parameter that can be invoked after the compilation is complete.Input ImageUsing Node JIMP – ROTATE()Before proceeding to use rotate() functions, please check that the ...
Read MoreHow to resize an image in Node Jimp?
NodeJS – Resize() is an inbuilt function that is used to resize the images to the desired size. We can use resize to set the height and width using a 2-pass bilinear algorithm. It can resize an image into any size as declared by the user. We can take input from the user or resize it into fixed Width*Height size.Syntaxresize(w, h, mode, cb)Definition of resize() paramtersw – This parameter is used to declare the width of the image. This is a required parameter.h – This parameter is used to declare the height of the resized image. This parameter is also required.mode – This ...
Read MoreHow to apply Posterize to an image in Node Jimp?
NodeJS – Posterize() is an inbuilt function that is used to apply posterize to images upto the level 'n'. The n will be the input parameter.Syntaxposterize(n, cb)Definition of posterize() paramtersn – It will take input to adjust the posterize level. Minimum value possible is 2.cb – This is an optional parameter that can be invoked after the compilation is complete.Input ImageUsing Node JIMP – POSTERIZE()Before proceeding to use posterize() functions, please check that the following statements are already executed for setting up the environment.npm init -y // Initialising the Node environmentnpm install jimp --save // Installing the jimp dependencyCreate a ...
Read MoreHow to change the opacity of an image in Node Jimp?
NodeJS – Opacity() is an inbuilt function that is used to change the opacity of the images. This function multiplies the opacity of each pixel by a factor between 0 and 1 to produce the output image.Syntaxopacity(f, cb)Definition of opacity() paramtersf – It takes a value between 0 to 1 as an input which will the paramtere to make the image opaque. Input 1 will make the image completely transparent.cb – This is also an optional parameter that can be invoked after the compilation is complete.Input ImageUsing Node JIMP – OPACITY()Before proceeding to use opacity() functions, please check that the following statements ...
Read MoreHow to invert the colors of an image in Node Jimp?
NodeJS – Invert() is an inbuilt function that is used to invert the image colors.Syntaxinvert(cb)sepia() paramtersb – This is an optional parameter that can be invoked after the compilation is complete.Input ImageUsing Node JIMP – INVERT()Before proceeding to use invert() functions, please check that the following statements are already executed for setting up the environment.npm init -y // Initialising the Node environmentnpm install jimp --save // Installing the jimp dependencyCreate an invert.js file and copy-paste the following code snippet in it.Use node invert.js to run the code.Note − The method name should match with the JS file name. Only then ...
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