ColdFusion implementation of intelligent string truncation - Smart truncation with word boundaries, custom suffixes, and multiple truncation positions (start, middle, end)

stringtruncate.cfm

<!---
    STRINGTRUNCATE Function
    
    Description: Intelligently truncates a string to a specified length while preserving word boundaries.
    Can add ellipsis or custom suffix, and optionally truncate from different positions (start, middle, end).
    
    Parameters:
        - text: The text to truncate (required)
        - maxLength: Maximum length of the result including suffix (required)
        - suffix: String to append when truncated (optional, default: "...")
        - position: Where to truncate - "end", "start", or "middle" (optional, default: "end")
        - breakWords: Allow breaking in middle of words (optional, default: false)
        - minWordLength: Minimum word length to preserve when not breaking words (optional, default: 4)
    
    Returns: Truncated string
    
    Usage:
        <cfset result = stringtruncate("Long text here", 10)>
        <cfset result = stringtruncate("Long text", 10, "…")>
        <cfset result = stringtruncate("Long text", 10, "...", "middle")>
    
    Examples:
        stringtruncate("Hello World", 8) returns "Hello..."
        stringtruncate("Hello World", 11, " →") returns "Hello →"
        stringtruncate("LongFilename.txt", 12, "...", "middle") returns "Long...txt"
    
    Author: DeveloperOffice.com
    Language: ColdFusion/Lucee
    License: MIT (https://opensource.org/licenses/MIT)
    Version: 1.0
--->

<cffunction name="stringtruncate" returntype="string" output="false">
    <cfargument name="text" type="string" required="true">
    <cfargument name="maxLength" type="numeric" required="true">
    <cfargument name="suffix" type="string" required="false" default="...">
    <cfargument name="position" type="string" required="false" default="end">
    <cfargument name="breakWords" type="boolean" required="false" default="false">
    <cfargument name="minWordLength" type="numeric" required="false" default="4">
    
    <cfset var result = arguments.text>
    <cfset var textLen = len(result)>
    <cfset var suffixLen = len(arguments.suffix)>
    
    <!--- If text is already short enough, return as-is --->
    <cfif textLen LTE arguments.maxLength>
        <cfreturn result>
    </cfif>
    
    <!--- Calculate available space for text --->
    <cfset var availableLength = arguments.maxLength - suffixLen>
    
    <!--- Ensure we have reasonable space for text --->
    <cfif availableLength LT 1>
        <!--- If suffix is longer than max length, just return truncated suffix --->
        <cfreturn left(arguments.suffix, arguments.maxLength)>
    </cfif>
    
    <!--- Handle different truncation positions --->
    <cfswitch expression="#lCase(arguments.position)#">
        
        <cfcase value="start">
            <!--- Truncate from start --->
            <cfif arguments.breakWords>
                <cfset result = arguments.suffix & right(result, availableLength)>
            <cfelse>
                <!--- Find word boundary from the start --->
                <cfset var startText = right(result, availableLength + 20)>
                <cfset var spacePos = find(" ", startText)>
                
                <cfif spacePos GT 0 AND spacePos LTE 20>
                    <cfset result = arguments.suffix & mid(startText, spacePos + 1, len(startText))>
                <cfelse>
                    <cfset result = arguments.suffix & right(result, availableLength)>
                </cfif>
            </cfif>
        </cfcase>
        
        <cfcase value="middle">
            <!--- Truncate from middle --->
            <cfset var halfLength = int(availableLength / 2)>
            <cfset var startPart = left(result, halfLength)>
            <cfset var endPart = right(result, halfLength)>
            
            <cfif NOT arguments.breakWords>
                <!--- Try to find word boundaries --->
                <cfset var startBoundary = len(startPart)>
                <cfset var endBoundary = 1>
                
                <!--- Find last space in start part --->
                <cfloop from="#len(startPart)#" to="1" index="i" step="-1">
                    <cfif mid(startPart, i, 1) EQ " ">
                        <cfset startBoundary = i - 1>
                        <cfbreak>
                    </cfif>
                </cfloop>
                
                <!--- Find first space in end part --->
                <cfloop from="1" to="#len(endPart)#" index="i">
                    <cfif mid(endPart, i, 1) EQ " ">
                        <cfset endBoundary = i + 1>
                        <cfbreak>
                    </cfif>
                </cfloop>
                
                <cfset startPart = left(startPart, startBoundary)>
                <cfset endPart = mid(endPart, endBoundary, len(endPart))>
            </cfif>
            
            <cfset result = startPart & arguments.suffix & endPart>
        </cfcase>
        
        <cfdefaultcase>
            <!--- Default: truncate from end --->
            <cfif arguments.breakWords>
                <cfset result = left(result, availableLength) & arguments.suffix>
            <cfelse>
                <!--- Find last complete word that fits --->
                <cfset var truncated = left(result, availableLength)>
                <cfset var lastSpace = 0>
                
                <!--- Look for last space --->
                <cfloop from="#len(truncated)#" to="1" index="i" step="-1">
                    <cfif mid(truncated, i, 1) EQ " ">
                        <cfset lastSpace = i>
                        <cfbreak>
                    </cfif>
                </cfloop>
                
                <!--- If we found a space and the remaining word is long enough --->
                <cfif lastSpace GT 0 AND lastSpace GTE arguments.minWordLength>
                    <cfset result = trim(left(result, lastSpace - 1)) & arguments.suffix>
                <cfelse>
                    <!--- No good break point found, check if we should break the word --->
                    <cfif availableLength GTE arguments.minWordLength>
                        <cfset result = left(result, availableLength) & arguments.suffix>
                    <cfelse>
                        <!--- Very short space, just use suffix --->
                        <cfset result = arguments.suffix>
                    </cfif>
                </cfif>
            </cfif>
        </cfdefaultcase>
        
    </cfswitch>
    
    <!--- Ensure result doesn't exceed max length --->
    <cfif len(result) GT arguments.maxLength>
        <cfset result = left(result, arguments.maxLength)>
    </cfif>
    
    <cfreturn result>
</cffunction>