[javascript] Split string in JavaScript and detect line break

I have a small function I found that takes a string from a textarea and then puts it into a canvas element and wraps the text when the line gets too long. But it doesn't detect line breaks. This is what it's doing and what it should do:

Input:

Hello

This is dummy text that could be inside the text area.
It will then get put into the canvas.

Wrong output:

Hello this is dummy text
that could be inside the
text area. It will then
get put into the canvas.

What it should output:

Hello

This is dummy text that
could be inside the text
area. It will then get
put into the canvas.

This is the function I'm using:

function wrapText(context, text, x, y, maxWidth, lineHeight) {
    var words = text.split(' ');
    var line = '';

    for(var n = 0; n < words.length; n++) {
        var testLine = line + words[n] + ' ';
        var metrics = context.measureText(testLine);
        var testWidth = metrics.width;
        if (testWidth > maxWidth && n > 0) {
            context.fillText(line, x, y);
            line = words[n] + ' ';
            y += lineHeight;
        }
        else {
            line = testLine;
        }
    }
    context.fillText(line, x, y);
}

Is it possible to achieve what I'm trying to get? Or is there a way to simply move the text area as is into the canvas?

This question is related to javascript string canvas split line-breaks

The answer is


You can use the split() function to break input on the basis of line break.

yourString.split("\n")

In case you need to split a string from your JSON, the string has the \n special character replaced with \\n.

Split string by newline:

Result.split('\n');

Split string received in JSON, where special character \n was replaced with \\n during JSON.stringify(in javascript) or json.json_encode(in PHP). So, if you have your string in a AJAX response, it was processed for transportation. and if it is not decoded, it will sill have the \n replaced with \\n** and you need to use:

Result.split('\\n');

Note that the debugger tools from your browser might not show this aspect as you was expecting, but you can see that splitting by \\n resulted in 2 entries as I need in my case: enter image description here


You should try detect the first line.

Then the:

if(n == 0){
  line = words[n]+"\n";
}

I'm not sure, but maybe it helps.


Split string in JavaScript

var array = str.match(/[^\r\n]+/g);

OR

var array = str.split(/\r?\n/);

Performance


Here's the final code I [OP] used. Probably not best practice, but it worked.

function wrapText(context, text, x, y, maxWidth, lineHeight) {

    var breaks = text.split('\n');
    var newLines = "";
    for(var i = 0; i < breaks.length; i ++){
      newLines = newLines + breaks[i] + ' breakLine ';
    }

    var words = newLines.split(' ');
    var line = '';
    console.log(words);
    for(var n = 0; n < words.length; n++) {
      if(words[n] != 'breakLine'){
        var testLine = line + words[n] + ' ';
        var metrics = context.measureText(testLine);
        var testWidth = metrics.width;
        if (testWidth > maxWidth && n > 0) {
          context.fillText(line, x, y);
          line = words[n] + ' ';
          y += lineHeight;
        }
        else {
          line = testLine;
        }
      }else{
          context.fillText(line, x, y);
          line = '';
          y += lineHeight;
      }
    }
    context.fillText(line, x, y);
  }

This is what I used to print text to a canvas. The input is not coming from a textarea, but from input and I'm only splitting by space. Definitely not perfect, but works for my case. It returns the lines in an array:

splitTextToLines: function (text) {
        var idealSplit = 7,
            maxSplit = 20,
            lineCounter = 0,
            lineIndex = 0,
            lines = [""],
            ch, i;

        for (i = 0; i < text.length; i++) {
            ch = text[i];
            if ((lineCounter >= idealSplit && ch === " ") || lineCounter >= maxSplit) {
                ch = "";
                lineCounter = -1;
                lineIndex++;
                lines.push("");
            }
            lines[lineIndex] += ch;
            lineCounter++;
        }

        return lines;
    }

Examples related to javascript

need to add a class to an element How to make a variable accessible outside a function? Hide Signs that Meteor.js was Used How to create a showdown.js markdown extension Please help me convert this script to a simple image slider Highlight Anchor Links when user manually scrolls? Summing radio input values How to execute an action before close metro app WinJS javascript, for loop defines a dynamic variable name Getting all files in directory with ajax

Examples related to string

How to split a string in two and store it in a field String method cannot be found in a main class method Kotlin - How to correctly concatenate a String Replacing a character from a certain index Remove quotes from String in Python Detect whether a Python string is a number or a letter How does String substring work in Swift How does String.Index work in Swift swift 3.0 Data to String? How to parse JSON string in Typescript

Examples related to canvas

How to make canvas responsive How to fill the whole canvas with specific color? Use HTML5 to resize an image before upload Convert canvas to PDF Scaling an image to fit on canvas Split string in JavaScript and detect line break Get distance between two points in canvas canvas.toDataURL() SecurityError Converting Chart.js canvas chart to image using .toDataUrl() results in blank image Chart.js canvas resize

Examples related to split

Parameter "stratify" from method "train_test_split" (scikit Learn) Pandas split DataFrame by column value How to split large text file in windows? Attribute Error: 'list' object has no attribute 'split' Split function in oracle to comma separated values with automatic sequence How would I get everything before a : in a string Python Split String by delimiter position using oracle SQL JavaScript split String with white space Split a String into an array in Swift? Split pandas dataframe in two if it has more than 10 rows

Examples related to line-breaks

HTML5 tag for horizontal line break Split string in JavaScript and detect line break Match linebreaks - \n or \r\n? How to linebreak an svg text within javascript? What is the difference between a "line feed" and a "carriage return"? Bash: Strip trailing linebreak from output How to read a file without newlines? How to break lines in PowerShell? How do I specify new lines on Python, when writing on files? How to remove line breaks (no characters!) from the string?