Added normalize transform option to normalize string spaces

README.md

@@ -220,6 +220,7 @@ A standalone string cannot be modified, i.e. `data = 'a'; ajv.validate(schema, d
 - `toLowerCase`: convert to lower case
 - `toUpperCase`: convert to upper case
 - `toEnumCase`: change string case to be equal to one of `enum` values in the schema
+- `normalizeSpaces`: replace all multiple white spaces with a single white space in a string
 
 Transformations are applied in the order they are listed.
 

spec/transform.spec.ts

@@ -131,6 +131,43 @@ describe('keyword "transform"', () => {
   })
 
   ajvs.forEach((ajv, i) => {
+    it(`should transform normalizeSpaces #${i}`, () => {
+      let schema, data
+
+      data = ["  normalize  object    to test  "]
+      schema = {type: "array", items: {type: "string", transform: ["normalizeSpaces"]}}
+      ajv.validate(schema, data).should.equal(true)
+      data.should.deep.equal([" normalize object to test "])
+
+      data = ["normalize"]
+      schema = {type: "array", items: {type: "string", transform: ["normalizeSpaces"]}}
+      ajv.validate(schema, data).should.equal(true)
+      data.should.deep.equal(["normalize"])
+
+      data = ["normalize object to test"]
+      schema = {type: "array", items: {type: "string", transform: ["normalizeSpaces"]}}
+      ajv.validate(schema, data).should.equal(true)
+      data.should.deep.equal(["normalize object to test"])
+
+      data = ["normalize  object to    test"]
+      schema = {type: "array", items: {type: "string", transform: ["normalizeSpaces"]}}
+      ajv.validate(schema, data).should.equal(true)
+      data.should.deep.equal(["normalize object to test"])
+
+      data = [
+        `A tab\t\tanother multiple tabs\t\t\t\tnew line
+multiple new lines
+
+
+
+Multiple spaces                   end`,
+      ]
+      schema = {type: "array", items: {type: "string", transform: ["normalizeSpaces"]}}
+      ajv.validate(schema, data).should.equal(true)
+      data.should.deep.equal([
+        "A tab another multiple tabs new line multiple new lines Multiple spaces end",
+      ])
+
     it(`shouldn't mutate the transform array of the schema while compiling it #${i}`, () => {
       const data = {p: "  trimObject  "}
       const schema = {type: "object", properties: {p: {type: "string", transform: ["trimLeft"]}}}

src/definitions/transform.ts

@@ -10,6 +10,7 @@ type TransformName =
   | "toLowerCase"
   | "toUpperCase"
   | "toEnumCase"
+  | "normalizeSpaces"
 
 interface TransformConfig {
   hash: Record<string, string | undefined>
@@ -26,6 +27,7 @@ const transform: {[key in TransformName]: Transform} = {
   toLowerCase: (s) => s.toLowerCase(),
   toUpperCase: (s) => s.toUpperCase(),
   toEnumCase: (s, cfg) => cfg?.hash[configKey(s)] || s,
+  normalizeSpaces: (s) => s.replace(/[\s\t\n]+/g, " "),
 }
 
 const getDef: (() => CodeKeywordDefinition) & {