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JavaScript - replace part of string from given index
2 points
In this article, we're going to have a look at how to replace part of a string from a given index in JavaScript.
Quick solution:
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var text = 'This is text.'2
var index = 2;3
var insert = '__';4
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var result = text.substring(0, index) + insert + text.substring(index + insert.length);6
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console.log(result);Note: read this article to know how to remove part of text for given indexes.
Check the below example for a better solution.
Presented in this section solution allows inserting text outside of given string filling space with any characters (by default with space).
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function repeatText(count, text) {2
var result = '';3
for (var i = 0; i < count; ++i) {4
result += text;5
}6
return result;7
}8
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function replaceText(text, insert, index, spacer) {10
if (spacer == null) {11
spacer = ' ';12
}13
var prefix = text.substring(0, index);14
var postfix = text.substring(index + insert.length);15
var space = repeatText(index - text.length, spacer);16
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return prefix + space + insert + postfix;18
}19
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// Usage example:21
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console.log( replaceText('This is text.', '__', 0) ); // __is is text.23
console.log( replaceText('This is text.', '__', 2) ); // Th__ is text.24
console.log( replaceText('This is text.', '__', 11) ); // This is tex__25
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console.log( replaceText('This is text.', '__', 13) ); // This is text.__27
console.log( replaceText('This is text.', '__', 15) ); // This is text. __28
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console.log( replaceText('text...', '__', 10, '++') ); // text...++++++__
ES 2015 introduced repeat() method for string.
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const replaceText = (text, insert, index, spacer = ' ') => {2
const prefix = text.substring(0, index);3
const postfix = text.substring(index + insert.length);4
const space = spacer.repeat(index < text.length ? 0 : index - text.length);5
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return prefix + space + insert + postfix;7
};8
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// Usage example:10
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console.log( replaceText('This is text.', '__', 0) ); // __is is text.12
console.log( replaceText('This is text.', '__', 2) ); // Th__ is text.13
console.log( replaceText('This is text.', '__', 11) ); // This is tex__14
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console.log( replaceText('This is text.', '__', 13) ); // This is text.__16
console.log( replaceText('This is text.', '__', 15) ); // This is text. __17
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console.log( replaceText('text...', '__', 10, '++') ); // text...++++++__
