diff --git a/_baseIsNative.js b/_baseIsNative.js
index 63b2fe17e..c80830c7b 100644
--- a/_baseIsNative.js
+++ b/_baseIsNative.js
@@ -23,10 +23,11 @@ const funcToString = funcProto.toString;
 const hasOwnProperty = objectProto.hasOwnProperty;
 
 /** Used to detect if a method is native. */
-const reIsNative = RegExp('^' +
-  funcToString.call(hasOwnProperty).replace(reRegExpChar, '\\$&')
-  .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?') + '$'
-);
+const reIsNative = RegExp(`^${
+  funcToString.call(hasOwnProperty)
+    .replace(reRegExpChar, '\\$&')
+    .replace(/hasOwnProperty|(function).*?(?=\\\()| for .+?(?=\\\])/g, '$1.*?')
+}$`);
 
 /**
  * The base implementation of `_.isNative` without bad shim checks.
diff --git a/_baseMerge.js b/_baseMerge.js
index dc1f309ab..844736406 100644
--- a/_baseMerge.js
+++ b/_baseMerge.js
@@ -27,7 +27,7 @@ function baseMerge(object, source, srcIndex, customizer, stack) {
     }
     else {
       const newValue = customizer
-        ? customizer(object[key], srcValue, (key + ''), object, source, stack)
+        ? customizer(object[key], srcValue, `${ key }`, object, source, stack)
         : undefined;
 
       if (newValue === undefined) {
diff --git a/_baseMergeDeep.js b/_baseMergeDeep.js
index a7962fbc7..ee8e345f9 100644
--- a/_baseMergeDeep.js
+++ b/_baseMergeDeep.js
@@ -38,7 +38,7 @@ function baseMergeDeep(object, source, key, srcIndex, mergeFunc, customizer, sta
     return;
   }
   var newValue = customizer
-    ? customizer(objValue, srcValue, (key + ''), object, source, stack)
+    ? customizer(objValue, srcValue, `${ key }`, object, source, stack)
     : undefined;
 
   var isCommon = newValue === undefined;
diff --git a/_baseRest.js b/_baseRest.js
index a31537100..1802b8ffe 100644
--- a/_baseRest.js
+++ b/_baseRest.js
@@ -11,7 +11,7 @@ import setToString from './_setToString.js';
  * @returns {Function} Returns the new function.
  */
 function baseRest(func, start) {
-  return setToString(overRest(func, start, identity), func + '');
+  return setToString(overRest(func, start, identity), `${ func }`);
 }
 
 export default baseRest;
diff --git a/_baseToString.js b/_baseToString.js
index 7b5b35c58..caf61fddf 100644
--- a/_baseToString.js
+++ b/_baseToString.js
@@ -4,11 +4,11 @@ import isArray from './isArray.js';
 import isSymbol from './isSymbol.js';
 
 /** Used as references for various `Number` constants. */
-var INFINITY = 1 / 0;
+const INFINITY = 1 / 0;
 
 /** Used to convert symbols to primitives and strings. */
-var symbolProto = Symbol ? Symbol.prototype : undefined,
-    symbolToString = symbolProto ? symbolProto.toString : undefined;
+const symbolProto = Symbol ? Symbol.prototype : undefined;
+const symbolToString = symbolProto ? symbolProto.toString : undefined;
 
 /**
  * The base implementation of `_.toString` which doesn't convert nullish
@@ -25,12 +25,12 @@ function baseToString(value) {
   }
   if (isArray(value)) {
     // Recursively convert values (susceptible to call stack limits).
-    return arrayMap(value, baseToString) + '';
+    return `${ arrayMap(value, baseToString) }`;
   }
   if (isSymbol(value)) {
     return symbolToString ? symbolToString.call(value) : '';
   }
-  var result = (value + '');
+  const result = `${ value }`;
   return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
 }
 
diff --git a/_createRound.js b/_createRound.js
index 2f1f64707..a8308aebf 100644
--- a/_createRound.js
+++ b/_createRound.js
@@ -20,11 +20,11 @@ function createRound(methodName) {
     if (precision) {
       // Shift with exponential notation to avoid floating-point issues.
       // See [MDN](https://mdn.io/round#Examples) for more details.
-      var pair = (toString(number) + 'e').split('e'),
-          value = func(pair[0] + 'e' + (+pair[1] + precision));
+      var pair = `${ toString(number) }e`.split('e'),
+          value = func(`${ pair[0] }e${ +pair[1] + precision }`);
 
-      pair = (toString(value) + 'e').split('e');
-      return +(pair[0] + 'e' + (+pair[1] - precision));
+      pair = `${ toString(value) }e`.split('e');
+      return +`${ pair[0] }e${ +pair[1] - precision }`;
     }
     return func(number);
   };
diff --git a/_equalByTag.js b/_equalByTag.js
index a7090ffe6..ad1200834 100644
--- a/_equalByTag.js
+++ b/_equalByTag.js
@@ -76,7 +76,7 @@ function equalByTag(object, other, tag, bitmask, customizer, equalFunc, stack) {
       // Coerce regexes to strings and treat strings, primitives and objects,
       // as equal. See http://www.ecma-international.org/ecma-262/7.0/#sec-regexp.prototype.tostring
       // for more details.
-      return object == (other + '');
+      return object == `${ other }`;
 
     case mapTag:
       var convert = mapToArray;
diff --git a/_escapeStringChar.js b/_escapeStringChar.js
index bec224996..164270a72 100644
--- a/_escapeStringChar.js
+++ b/_escapeStringChar.js
@@ -16,7 +16,7 @@ var stringEscapes = {
  * @returns {string} Returns the escaped character.
  */
 function escapeStringChar(chr) {
-  return '\\' + stringEscapes[chr];
+  return `\\${ stringEscapes[chr] }`;
 }
 
 export default escapeStringChar;
diff --git a/_flatRest.js b/_flatRest.js
index 45dc4390b..b9122fb64 100644
--- a/_flatRest.js
+++ b/_flatRest.js
@@ -10,7 +10,7 @@ import setToString from './_setToString.js';
  * @returns {Function} Returns the new function.
  */
 function flatRest(func) {
-  return setToString(overRest(func, undefined, flatten), func + '');
+  return setToString(overRest(func, undefined, flatten), `${ func }`);
 }
 
 export default flatRest;
diff --git a/_getFuncName.js b/_getFuncName.js
index 06e2a3d9e..fbb666182 100644
--- a/_getFuncName.js
+++ b/_getFuncName.js
@@ -14,7 +14,7 @@ var hasOwnProperty = objectProto.hasOwnProperty;
  * @returns {string} Returns the function name.
  */
 function getFuncName(func) {
-  var result = (func.name + ''),
+  var result = `${ func.name }`,
       array = realNames[result],
       length = hasOwnProperty.call(realNames, result) ? array.length : 0;
 
diff --git a/_hasUnicode.js b/_hasUnicode.js
index c0808981e..ba37a3236 100644
--- a/_hasUnicode.js
+++ b/_hasUnicode.js
@@ -10,7 +10,7 @@ var rsAstralRange = '\\ud800-\\udfff',
 var rsZWJ = '\\u200d';
 
 /** Used to detect strings with [zero-width joiners or code points from the astral planes](http://eev.ee/blog/2015/09/12/dark-corners-of-unicode/). */
-var reHasUnicode = RegExp('[' + rsZWJ + rsAstralRange  + rsComboRange + rsVarRange + ']');
+var reHasUnicode = RegExp(`[${ rsZWJ + rsAstralRange + rsComboRange + rsVarRange }]`;
 
 /**
  * Checks if `string` contains Unicode symbols.
diff --git a/_insertWrapDetails.js b/_insertWrapDetails.js
index 5191b7aba..39c9e8cf8 100644
--- a/_insertWrapDetails.js
+++ b/_insertWrapDetails.js
@@ -10,14 +10,14 @@ var reWrapComment = /\{(?:\n\/\* \[wrapped with .+\] \*\/)?\n?/;
  * @returns {string} Returns the modified source.
  */
 function insertWrapDetails(source, details) {
-  var length = details.length;
+  const length = details.length;
   if (!length) {
     return source;
   }
-  var lastIndex = length - 1;
+  const lastIndex = length - 1;
   details[lastIndex] = (length > 1 ? '& ' : '') + details[lastIndex];
   details = details.join(length > 2 ? ', ' : ' ');
-  return source.replace(reWrapComment, '{\n/* [wrapped with ' + details + '] */\n');
+  return source.replace(reWrapComment, `{\n/* [wrapped with ${ details }] */\n`);
 }
 
 export default insertWrapDetails;
diff --git a/_isMasked.js b/_isMasked.js
index ffc1a3dfa..f66a96c65 100644
--- a/_isMasked.js
+++ b/_isMasked.js
@@ -2,8 +2,8 @@ import coreJsData from './_coreJsData.js';
 
 /** Used to detect methods masquerading as native. */
 var maskSrcKey = ((() => {
-  var uid = /[^.]+$/.exec(coreJsData && coreJsData.keys && coreJsData.keys.IE_PROTO || '');
-  return uid ? ('Symbol(src)_1.' + uid) : '';
+  const uid = /[^.]+$/.exec(coreJsData && coreJsData.keys && coreJsData.keys.IE_PROTO || '');
+  return uid ? `Symbol(src)_1.${ uid }` : '';
 })());
 
 /**
diff --git a/_setWrapToString.js b/_setWrapToString.js
index 16b08fdd4..5afcb6be0 100644
--- a/_setWrapToString.js
+++ b/_setWrapToString.js
@@ -14,7 +14,7 @@ import updateWrapDetails from './_updateWrapDetails.js';
  * @returns {Function} Returns `wrapper`.
  */
 function setWrapToString(wrapper, reference, bitmask) {
-  var source = (reference + '');
+  const source = `${ reference }`;
   return setToString(wrapper, insertWrapDetails(source, updateWrapDetails(getWrapDetails(source), bitmask)));
 }
 
diff --git a/_toKey.js b/_toKey.js
index 295277f63..66d4630f0 100644
--- a/_toKey.js
+++ b/_toKey.js
@@ -14,7 +14,7 @@ function toKey(value) {
   if (typeof value == 'string' || isSymbol(value)) {
     return value;
   }
-  var result = (value + '');
+  const result = `${ value }`;
   return (result == '0' && (1 / value) == -INFINITY) ? '-0' : result;
 }
 
diff --git a/_toSource.js b/_toSource.js
index 2696f7aff..c1527cfa4 100644
--- a/_toSource.js
+++ b/_toSource.js
@@ -17,7 +17,7 @@ function toSource(func) {
       return funcToString.call(func);
     } catch (e) {}
     try {
-      return (func + '');
+      return `${ func }`;
     } catch (e) {}
   }
   return '';
diff --git a/_unicodeSize.js b/_unicodeSize.js
index 8c0317541..8b14af37c 100644
--- a/_unicodeSize.js
+++ b/_unicodeSize.js
@@ -1,30 +1,30 @@
 /** Used to compose unicode character classes. */
-var rsAstralRange = '\\ud800-\\udfff',
-    rsComboMarksRange = '\\u0300-\\u036f',
-    reComboHalfMarksRange = '\\ufe20-\\ufe2f',
-    rsComboSymbolsRange = '\\u20d0-\\u20ff',
-    rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange,
-    rsVarRange = '\\ufe0e\\ufe0f';
+const rsAstralRange = '\\ud800-\\udfff';
+const rsComboMarksRange = '\\u0300-\\u036f';
+const reComboHalfMarksRange = '\\ufe20-\\ufe2f';
+const rsComboSymbolsRange = '\\u20d0-\\u20ff';
+const rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange;
+const rsVarRange = '\\ufe0e\\ufe0f';
 
 /** Used to compose unicode capture groups. */
-var rsAstral = '[' + rsAstralRange + ']',
-    rsCombo = '[' + rsComboRange + ']',
-    rsFitz = '\\ud83c[\\udffb-\\udfff]',
-    rsModifier = '(?:' + rsCombo + '|' + rsFitz + ')',
-    rsNonAstral = '[^' + rsAstralRange + ']',
-    rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}',
-    rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]',
-    rsZWJ = '\\u200d';
+const rsAstral = `[${ rsAstralRange }]`;
+const rsCombo = `[${ rsComboRange }]`;
+const rsFitz = '\\ud83c[\\udffb-\\udfff]';
+const rsModifier = `(?:${ rsCombo }|${ rsFitz })`;
+const rsNonAstral = `[^${ rsAstralRange }]`;
+const rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}';
+const rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]';
+const rsZWJ = '\\u200d';
 
 /** Used to compose unicode regexes. */
-var reOptMod = rsModifier + '?',
-    rsOptVar = '[' + rsVarRange + ']?',
-    rsOptJoin = '(?:' + rsZWJ + '(?:' + [rsNonAstral, rsRegional, rsSurrPair].join('|') + ')' + rsOptVar + reOptMod + ')*',
-    rsSeq = rsOptVar + reOptMod + rsOptJoin,
-    rsSymbol = '(?:' + [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') + ')';
+const reOptMod = `${ rsModifier }?`;
+const rsOptVar = `[${ rsVarRange }]?`;
+const rsOptJoin = `(?:${ rsZWJ }(?:${ [rsNonAstral, rsRegional, rsSurrPair].join('|') })${ rsOptVar + reOptMod })*`;
+const rsSeq = rsOptVar + reOptMod + rsOptJoin;
+const rsSymbol = `(?:${ [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') })`;
 
 /** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
-var reUnicode = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');
+const reUnicode = RegExp(`${ rsFitz }(?=${ rsFitz })|${ rsSymbol + rsSeq }`, 'g');
 
 /**
  * Gets the size of a Unicode `string`.
@@ -34,7 +34,7 @@ var reUnicode = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');
  * @returns {number} Returns the string size.
  */
 function unicodeSize(string) {
-  var result = reUnicode.lastIndex = 0;
+  let result = reUnicode.lastIndex = 0;
   while (reUnicode.test(string)) {
     ++result;
   }
diff --git a/_unicodeToArray.js b/_unicodeToArray.js
index ea4976206..2d6f9f9f0 100644
--- a/_unicodeToArray.js
+++ b/_unicodeToArray.js
@@ -1,30 +1,30 @@
 /** Used to compose unicode character classes. */
-var rsAstralRange = '\\ud800-\\udfff',
-    rsComboMarksRange = '\\u0300-\\u036f',
-    reComboHalfMarksRange = '\\ufe20-\\ufe2f',
-    rsComboSymbolsRange = '\\u20d0-\\u20ff',
-    rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange,
-    rsVarRange = '\\ufe0e\\ufe0f';
+const rsAstralRange = '\\ud800-\\udfff';
+const rsComboMarksRange = '\\u0300-\\u036f';
+const reComboHalfMarksRange = '\\ufe20-\\ufe2f';
+const rsComboSymbolsRange = '\\u20d0-\\u20ff';
+const rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange;
+const rsVarRange = '\\ufe0e\\ufe0f';
 
 /** Used to compose unicode capture groups. */
-var rsAstral = '[' + rsAstralRange + ']',
-    rsCombo = '[' + rsComboRange + ']',
-    rsFitz = '\\ud83c[\\udffb-\\udfff]',
-    rsModifier = '(?:' + rsCombo + '|' + rsFitz + ')',
-    rsNonAstral = '[^' + rsAstralRange + ']',
-    rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}',
-    rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]',
-    rsZWJ = '\\u200d';
+const rsAstral = `[${ rsAstralRange }]`;
+const rsCombo = `[${ rsComboRange }]`;
+const rsFitz = '\\ud83c[\\udffb-\\udfff]';
+const rsModifier = `(?:${ rsCombo }|${ rsFitz })`;
+const rsNonAstral = `[^${ rsAstralRange }]`;
+const rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}';
+const rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]';
+const rsZWJ = '\\u200d';
 
 /** Used to compose unicode regexes. */
-var reOptMod = rsModifier + '?',
-    rsOptVar = '[' + rsVarRange + ']?',
-    rsOptJoin = '(?:' + rsZWJ + '(?:' + [rsNonAstral, rsRegional, rsSurrPair].join('|') + ')' + rsOptVar + reOptMod + ')*',
-    rsSeq = rsOptVar + reOptMod + rsOptJoin,
-    rsSymbol = '(?:' + [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') + ')';
+const reOptMod = `${ rsModifier }?`;
+const rsOptVar = `[${ rsVarRange }]?`;
+const rsOptJoin = `(?:${ rsZWJ }(?:${ [rsNonAstral, rsRegional, rsSurrPair].join('|') })${ rsOptVar + reOptMod })*`;
+const rsSeq = rsOptVar + reOptMod + rsOptJoin;
+const rsSymbol = `(?:${ [rsNonAstral + rsCombo + '?', rsCombo, rsRegional, rsSurrPair, rsAstral].join('|') })`;
 
 /** Used to match [string symbols](https://mathiasbynens.be/notes/javascript-unicode). */
-var reUnicode = RegExp(rsFitz + '(?=' + rsFitz + ')|' + rsSymbol + rsSeq, 'g');
+const reUnicode = RegExp(`${ rsFitz }(?=${ rsFitz })|${ rsSymbol + rsSeq }`, 'g');
 
 /**
  * Converts a Unicode `string` to an array.
diff --git a/_unicodeWords.js b/_unicodeWords.js
index 99acbefc2..bf152d284 100644
--- a/_unicodeWords.js
+++ b/_unicodeWords.js
@@ -1,54 +1,54 @@
 /** Used to compose unicode character classes. */
-var rsAstralRange = '\\ud800-\\udfff',
-    rsComboMarksRange = '\\u0300-\\u036f',
-    reComboHalfMarksRange = '\\ufe20-\\ufe2f',
-    rsComboSymbolsRange = '\\u20d0-\\u20ff',
-    rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange,
-    rsDingbatRange = '\\u2700-\\u27bf',
-    rsLowerRange = 'a-z\\xdf-\\xf6\\xf8-\\xff',
-    rsMathOpRange = '\\xac\\xb1\\xd7\\xf7',
-    rsNonCharRange = '\\x00-\\x2f\\x3a-\\x40\\x5b-\\x60\\x7b-\\xbf',
-    rsPunctuationRange = '\\u2000-\\u206f',
-    rsSpaceRange = ' \\t\\x0b\\f\\xa0\\ufeff\\n\\r\\u2028\\u2029\\u1680\\u180e\\u2000\\u2001\\u2002\\u2003\\u2004\\u2005\\u2006\\u2007\\u2008\\u2009\\u200a\\u202f\\u205f\\u3000',
-    rsUpperRange = 'A-Z\\xc0-\\xd6\\xd8-\\xde',
-    rsVarRange = '\\ufe0e\\ufe0f',
-    rsBreakRange = rsMathOpRange + rsNonCharRange + rsPunctuationRange + rsSpaceRange;
+const rsAstralRange = '\\ud800-\\udfff';
+const rsComboMarksRange = '\\u0300-\\u036f';
+const reComboHalfMarksRange = '\\ufe20-\\ufe2f';
+const rsComboSymbolsRange = '\\u20d0-\\u20ff';
+const rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange;
+const rsDingbatRange = '\\u2700-\\u27bf';
+const rsLowerRange = 'a-z\\xdf-\\xf6\\xf8-\\xff';
+const rsMathOpRange = '\\xac\\xb1\\xd7\\xf7';
+const rsNonCharRange = '\\x00-\\x2f\\x3a-\\x40\\x5b-\\x60\\x7b-\\xbf';
+const rsPunctuationRange = '\\u2000-\\u206f';
+const rsSpaceRange = ' \\t\\x0b\\f\\xa0\\ufeff\\n\\r\\u2028\\u2029\\u1680\\u180e\\u2000\\u2001\\u2002\\u2003\\u2004\\u2005\\u2006\\u2007\\u2008\\u2009\\u200a\\u202f\\u205f\\u3000';
+const rsUpperRange = 'A-Z\\xc0-\\xd6\\xd8-\\xde';
+const rsVarRange = '\\ufe0e\\ufe0f';
+const rsBreakRange = rsMathOpRange + rsNonCharRange + rsPunctuationRange + rsSpaceRange;
 
 /** Used to compose unicode capture groups. */
-var rsApos = "['\u2019]",
-    rsBreak = '[' + rsBreakRange + ']',
-    rsCombo = '[' + rsComboRange + ']',
-    rsDigits = '\\d+',
-    rsDingbat = '[' + rsDingbatRange + ']',
-    rsLower = '[' + rsLowerRange + ']',
-    rsMisc = '[^' + rsAstralRange + rsBreakRange + rsDigits + rsDingbatRange + rsLowerRange + rsUpperRange + ']',
-    rsFitz = '\\ud83c[\\udffb-\\udfff]',
-    rsModifier = '(?:' + rsCombo + '|' + rsFitz + ')',
-    rsNonAstral = '[^' + rsAstralRange + ']',
-    rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}',
-    rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]',
-    rsUpper = '[' + rsUpperRange + ']',
-    rsZWJ = '\\u200d';
+const rsApos = "['\u2019]";
+const rsBreak = `[${ rsBreakRange }]`;
+const rsCombo = `[${ rsComboRange }]`;
+const rsDigits = '\\d+';
+const rsDingbat = `[${ rsDingbatRange }]`;
+const rsLower = `[${ rsLowerRange }]`;
+const rsMisc = `[^${ rsAstralRange }${ rsBreakRange + rsDigits + rsDingbatRange + rsLowerRange + rsUpperRange }]`;
+const rsFitz = '\\ud83c[\\udffb-\\udfff]';
+const rsModifier = `(?:${ rsCombo }|${ rsFitz })`;
+const rsNonAstral = `[^${ rsAstralRange }]`;
+const rsRegional = '(?:\\ud83c[\\udde6-\\uddff]){2}';
+const rsSurrPair = '[\\ud800-\\udbff][\\udc00-\\udfff]';
+const rsUpper = `[${ rsUpperRange }]`;
+const rsZWJ = '\\u200d';
 
 /** Used to compose unicode regexes. */
-var rsMiscLower = '(?:' + rsLower + '|' + rsMisc + ')',
-    rsMiscUpper = '(?:' + rsUpper + '|' + rsMisc + ')',
-    rsOptContrLower = '(?:' + rsApos + '(?:d|ll|m|re|s|t|ve))?',
-    rsOptContrUpper = '(?:' + rsApos + '(?:D|LL|M|RE|S|T|VE))?',
-    reOptMod = rsModifier + '?',
-    rsOptVar = '[' + rsVarRange + ']?',
-    rsOptJoin = '(?:' + rsZWJ + '(?:' + [rsNonAstral, rsRegional, rsSurrPair].join('|') + ')' + rsOptVar + reOptMod + ')*',
-    rsOrdLower = '\\d*(?:(?:1st|2nd|3rd|(?![123])\\dth)\\b)',
-    rsOrdUpper = '\\d*(?:(?:1ST|2ND|3RD|(?![123])\\dTH)\\b)',
-    rsSeq = rsOptVar + reOptMod + rsOptJoin,
-    rsEmoji = '(?:' + [rsDingbat, rsRegional, rsSurrPair].join('|') + ')' + rsSeq;
+const rsMiscLower = `(?:${ rsLower }|${ rsMisc })`;
+const rsMiscUpper = `(?:${ rsUpper }|${ rsMisc })`;
+const rsOptContrLower = `(?:${ rsApos }(?:d|ll|m|re|s|t|ve))?`;
+const rsOptContrUpper = `(?:${ rsApos }(?:D|LL|M|RE|S|T|VE))?`;
+const reOptMod = `${ rsModifier }?`;
+const rsOptVar = `[${ rsVarRange }]?`;
+const rsOptJoin = `(?:${ rsZWJ }(?:${ [rsNonAstral, rsRegional, rsSurrPair].join('|') })${ rsOptVar + reOptMod })*`;
+const rsOrdLower = '\\d*(?:(?:1st|2nd|3rd|(?![123])\\dth)\\b)';
+const rsOrdUpper = '\\d*(?:(?:1ST|2ND|3RD|(?![123])\\dTH)\\b)';
+const rsSeq = rsOptVar + reOptMod + rsOptJoin;
+const rsEmoji = `(?:${ [rsDingbat, rsRegional, rsSurrPair].join('|') })${ rsSeq }`;
 
 /** Used to match complex or compound words. */
-var reUnicodeWord = RegExp([
-  rsUpper + '?' + rsLower + '+' + rsOptContrLower + '(?=' + [rsBreak, rsUpper, '$'].join('|') + ')',
-  rsMiscUpper + '+' + rsOptContrUpper + '(?=' + [rsBreak, rsUpper + rsMiscLower, '$'].join('|') + ')',
-  rsUpper + '?' + rsMiscLower + '+' + rsOptContrLower,
-  rsUpper + '+' + rsOptContrUpper,
+const reUnicodeWord = RegExp([
+  `${ rsUpper }?${ rsLower }+${ rsOptContrLower }(?=${ [rsBreak, rsUpper, '$'].join('|') })`,
+  `${ rsMiscUpper }+${ rsOptContrUpper }(?=${ [rsBreak, rsUpper + rsMiscLower, '$'].join('|') })`,
+  `${ rsUpper }?${ rsMiscLower}+${ rsOptContrLower }`,
+  `${ rsUpper }+${ rsOptContrUpper }`,
   rsOrdUpper,
   rsOrdLower,
   rsDigits,
diff --git a/_updateWrapDetails.js b/_updateWrapDetails.js
index 8a670cded..9e009e9c7 100644
--- a/_updateWrapDetails.js
+++ b/_updateWrapDetails.js
@@ -35,7 +35,7 @@ var wrapFlags = [
  */
 function updateWrapDetails(details, bitmask) {
   arrayEach(wrapFlags, pair => {
-    var value = '_.' + pair[0];
+    var value = `_.${ pair[0] }`;
     if ((bitmask & pair[1]) && !arrayIncludes(details, value)) {
       details.push(value);
     }
diff --git a/deburr.js b/deburr.js
index 73dc9b374..636fc4739 100644
--- a/deburr.js
+++ b/deburr.js
@@ -2,22 +2,22 @@ import deburrLetter from './_deburrLetter.js';
 import toString from './toString.js';
 
 /** Used to match Latin Unicode letters (excluding mathematical operators). */
-var reLatin = /[\xc0-\xd6\xd8-\xf6\xf8-\xff\u0100-\u017f]/g;
+const reLatin = /[\xc0-\xd6\xd8-\xf6\xf8-\xff\u0100-\u017f]/g;
 
 /** Used to compose unicode character classes. */
-var rsComboMarksRange = '\\u0300-\\u036f',
-    reComboHalfMarksRange = '\\ufe20-\\ufe2f',
-    rsComboSymbolsRange = '\\u20d0-\\u20ff',
-    rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange;
+const rsComboMarksRange = '\\u0300-\\u036f';
+const reComboHalfMarksRange = '\\ufe20-\\ufe2f';
+const rsComboSymbolsRange = '\\u20d0-\\u20ff';
+const rsComboRange = rsComboMarksRange + reComboHalfMarksRange + rsComboSymbolsRange;
 
 /** Used to compose unicode capture groups. */
-var rsCombo = '[' + rsComboRange + ']';
+const rsCombo = `[${ rsComboRange }]`;
 
 /**
  * Used to match [combining diacritical marks](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks) and
  * [combining diacritical marks for symbols](https://en.wikipedia.org/wiki/Combining_Diacritical_Marks_for_Symbols).
  */
-var reComboMark = RegExp(rsCombo, 'g');
+const reComboMark = RegExp(rsCombo, 'g');
 
 /**
  * Deburrs `string` by converting
diff --git a/template.js b/template.js
index 03bb8843f..6598b846f 100644
--- a/template.js
+++ b/template.js
@@ -162,7 +162,7 @@ function template(string, options, guard) {
   , 'g');
 
   // Use a sourceURL for easier debugging.
-  var sourceURL = 'sourceURL' in options ? '//# sourceURL=' + options.sourceURL + '\n' : '';
+  var sourceURL = 'sourceURL' in options ? `//# sourceURL=${ options.sourceURL }\n` : '';
 
   string.replace(reDelimiters, (
     match,
@@ -180,14 +180,14 @@ function template(string, options, guard) {
     // Replace delimiters with snippets.
     if (escapeValue) {
       isEscaping = true;
-      source += "' +\n__e(" + escapeValue + ") +\n'";
+      source += `' +\n__e(${ escapeValue }) +\n'`;
     }
     if (evaluateValue) {
       isEvaluating = true;
-      source += "';\n" + evaluateValue + ";\n__p += '";
+      source += `';\n${ evaluateValue };\n__p += '`;
     }
     if (interpolateValue) {
-      source += "' +\n((__t = (" + interpolateValue + ")) == null ? '' : __t) +\n'";
+      source += `' +\n((__t = (${ interpolateValue })) == null ? '' : __t) +\n'`;
     }
     index = offset + match.length;
 
@@ -202,7 +202,7 @@ function template(string, options, guard) {
   // code to add the data object to the top of the scope chain.
   var variable = options.variable;
   if (!variable) {
-    source = 'with (obj) {\n' + source + '\n}\n';
+    source = `with (obj) {\n${ source }\n}\n`;
   }
   // Cleanup code by stripping empty strings.
   source = (isEvaluating ? source.replace(reEmptyStringLeading, '') : source)
@@ -210,7 +210,7 @@ function template(string, options, guard) {
     .replace(reEmptyStringTrailing, '$1;');
 
   // Frame code as the function body.
-  source = 'function(' + (variable || 'obj') + ') {\n' +
+  source = `function(${ variable || 'obj' }) {\n` +
     (variable
       ? ''
       : 'obj || (obj = {});\n'
@@ -228,8 +228,7 @@ function template(string, options, guard) {
     source +
     'return __p\n}';
 
-  var result = attempt(() => Function(importsKeys, sourceURL + 'return ' + source)
-    .apply(undefined, importsValues));
+  var result = attempt(() => Function(importsKeys, `${ sourceURL }return ${ source }`))(...importsValues);
 
   // Provide the compiled function's source by its `toString` method or
   // the `source` property as a convenience for inlining compiled templates.
diff --git a/toNumber.js b/toNumber.js
index 430bf226c..7f682ea9c 100644
--- a/toNumber.js
+++ b/toNumber.js
@@ -51,7 +51,7 @@ function toNumber(value) {
   }
   if (isObject(value)) {
     var other = typeof value.valueOf == 'function' ? value.valueOf() : value;
-    value = isObject(other) ? (other + '') : other;
+    value = isObject(other) ? `${ other }` : other;
   }
   if (typeof value != 'string') {
     return value === 0 ? value : +value;
diff --git a/truncate.js b/truncate.js
index fe4156175..cee98d6cc 100644
--- a/truncate.js
+++ b/truncate.js
@@ -91,7 +91,7 @@ function truncate(string, options) {
           substring = result;
 
       if (!separator.global) {
-        separator = RegExp(separator.source, toString(reFlags.exec(separator)) + 'g');
+        separator = RegExp(separator.source, `${ toString(reFlags.exec(separator)) }g`);
       }
       separator.lastIndex = 0;
       while ((match = separator.exec(substring))) {